Abstract: Benzoic acid derivatives of the formula I 1

Abstract: Diacyl-substituted guanidines of the formula I are described where X(1) and X(2) are as defined herein. The compounds are suitable for use as antiarrhythmic pharmaceuticals possessing a cardioprotective component for the prophylaxis and treatment of infarction and for the treatment of angina pectoris, in connection with which they also inhibit or strongly reduce, in a preventitive manner the pathophysiological processes associated with the genesis of ischemically induced damage, in particular associated with the elicitation of ischemically induced cardiac arrhythmias.

Abstract: The subject invention involves novel acyl isothiocyanate resins of formula (I) and processes for making them: (a) starting with a phenyl carboxy resin, treating the resin with any reagent that converts the carboxy to an acyl halide, followed by treatment with tetranikylammonium thiocyanate or an alkali metal salt thereof, to provide the acyl isothiocyanate resin. The subject invention also involves processes for making guanidine compounds and related cyclized compounds using an acyl isothiocyanate resin, comprising the following steps: (b) reacting the acyl isothiocyanate resin with a primary amine; (c) reacting the product from Step (b) with a sulfur activating agent and ammonia or a primary or secondary amine; (d) treating the product from Step (c) with a strong base or medium strength acid to cleave product from the resin, providing the guanidine compound or/and the related cyclized compound.

Abstract: A compound represented by the general formula (1): wherein each of R1, R2, R3, R4 and R5 is a hydrogen atom, an alkyl group, a substituted alkyl group, an alkenyl group, an alkynyl group, a cycloalkyl group, a cycloalkenyl group, a saturated heterocyclic group, an aromatic group, an acyl group or the like; each of Y1, Y2, Y3 and Y4 is a single bond, —CH2—, —O—, —CO— or the like, provided that at least two of Y1 through Y4 are independently a group other than a single bond; and Z may be absent, or one or more Zs may be present and are independently an alkyl group, a substituted alkyl group, an alkenyl group, an alkynyl group, a cycloalkyl group, a cycloalkenyl group, a saturated heterocyclic group, a halogen atom, a carboxyl group, an alkoxycarbonyl group, an aromatic group, an acyl group or the like, is useful as a therapeutic or prophylactic agent for diseases caused by the acceleration of the sodium/proton exchange transport system.

Abstract: A compound of the formula: wherein R1 is hydrogen or halogen, R2 is hydroxy, acyl(lower)alkoxy, hydroxy(lower)alkyl, lower alkoxy(lower)alkyl, lower alkylthio(lower)alkyl, mono(or di or tri)halo(lower)alkyl, (ethoxycarbonyl)amino, sulfamoylamino, (dimethylsulfamoyl)amino, N,N-di(lower)alkylamino(lower)alkyl, hydroxyimino(lower)alkyl, lower alkoxyimino(lower)alkyl, acyl, lower alkoxycarbonyl, carbamoyl, di(lower)alkylcarbamoyl, (amino(lower)alkyl)carbamoyl, N,N-di(lower)alkylamino(lower)alkylcarbamoyl, guanidinocarbonyl, morpholinylsulfonyl, sulfamoyl, lower alkylsulfamoyl, (lower alkylsulfonyl)(lower)alkyl, guanidinocarbonyl(lower)alkenyl, lower alkylthio, cyano, acyl(lower)alkyl, acyl(lower)alkenyl, aryl which has one or more substituent(s) or a heterocyclic group which has one or more substituent(s), and X is —O—, or a salt thereof.

Abstract: The present invention provides therapeutically useful substituted guanidines, and methods of treatment and pharmaceutical compositions that utilize or comprise one or more of such guanidines.

Abstract: The invention relates to a compound of formula (1), 1

Abstract: Tri- and tetra-substituted guanidines which exhibit a high binding affinity to phencyclidine (PCP) receptors and, more preferably, low affinity to the brain sigma receptors. These guanidine derivatives act as non-competitive inhibitors of glutamate induced responses of the NMDA receptor by acting as blockers for the ion channel of the NMDA receptor-ion channel complex. These compounds thus exert neuroprotective activity and are useful in the therapeutic treatment of neuronal loss in hypoxia, hypoglycemia, brain or spinal cord ischemia, and brain or spinal chord trauma as well as being useful for the treatment of epilepsy, Alzheimer's disease, Amyotrophic Lateral Sclerosis, Parkinson's disease, Huntington's disease, Down's Syndrome, Korsakoff's disease and other neurodegenerative disorders.

Abstract: Hexasubstituted guanidinium chlorides are prepared by a method which affords them in high yield as aqueous solutions, optionally also containing alkali metal chlorides. The solutions may be employed as sources of hexasubstituted guanidinium salts useful as phase transfer catalysts for the reaction of alkali metal salts of dihydroxyaromatic compounds with substituted imides to form polyetherimides or their intermediates.

Abstract: Non-peptide GnRH agents capable of inhibiting the effect of gonadotropin-releasing hormone are of the following general formula, where X1, X2, Y, and are defined variables: Such compounds and their pharmaceutically acceptable salts, multimers, prodrugs, and active metabolites are suitable for treating mammalian reproductive disorders and steroid hormone-dependent tumors as well as for regulating fertility, where suppression of gonadotropin release is indicated. Methods for synthesizing the compounds and intermediates useful in their preparation are also described.

Abstract: The present invention provides peptide aldehydes having an 3-amino-2-hydro yenyl acetamide group as part of the peptide backbone d an arginine group or analog at P1. These compounds e potent and specific or inhibitors of thrombin. Ther pharmaceutically acceptable salts, pharmaceutic ly acceptable compositions thereof, and methods of using t as therapeutic agents for disease states in mammals charachterized by abnormal thrombosis are also described. Also described are 3-amino-2-hydroxyphenyl-acetamide derivatives having in history activity towards proteases of the trypsin/chymotrypsin class.

Abstract: A guanidine derivative represented by formula (1), (2), (3) or its acid addition salt and a production process thereof wherein each of A and B is a C2-C8 alkylene, D is a single bond, —CO— or a C1-C6 alkylene, E is H, a lower alkyl or the like, m is 1 to 6, n is 0 to 6 and R1 is H, a lower alkyl or the like, 1 is 1 to 10 and G is H, —OH or the like and a skin cosmetic containing the same. It can exert excellent keratin layer softening effect continuously for a long period of time.

Abstract: The present invention provides therapeutically useful substituted guanidines, and methods of treatment and pharmaceutical compositions that utilize or comprise one or more of such guanidines.

Abstract: Compounds of the invention having general formula ##STR1## are useful reagents for protecting amine, guanidine, amidine or hydroxyl groups during organic synthesis. In particular, compounds are useful during oligonucleotide synthesis to protect nucleobase amines as well as tethered amines used for attaching functional moieties to oligonucleotides.

Abstract: This invention is directed to benzamidine derivatives substituted by amino acid and hydroxy acid derivatives which are useful as anti-coagulants. This invention is also directed to pharmaceutical compositions containing the compounds of the invention, and methods of using the compounds to treat disease-states characterized by thrombotic activity.

Abstract: There are described benzoylguanidines of the formula I ##STR1## where R(1) is R(4)--SO.sub.m, R(5)R(6)N--SO.sub.2 --; O.sub.p --(CH.sub.2).sub.q --(CF.sub.2).sub.r --CF.sub.3 ; --SR(10), --OR(10) or --CR(10)R(11)R(12); R(2) is --(CH.sub.2).sub.u --(CF.sub.2).sub.t --CF.sub.3 ; R(3) is hydrogen or independently defined as R(1); and their pharmaceutically tolerable salts. They are obtained by reaction of a compound of the formula II ##STR2## with guanidine. They are compounds of outstanding activity on the cardiovascular system.

Abstract: The instant invention is directed to a single, selectively N-alkylated compound and libraries of such compounds as set forth in Formula I. Furthermore, the instant invention is directed to methods of effecting analgesia, a decrease in the postprandial rise in the blood glucose levels of a mammal after ingestion of a carbohydrate load by said mammal, and treating microbial infections, utilizing such a single compound of Formula I in conjunction with a pharmaceutically-acceptable carrier. Also, the instant invention is directed to methods for selective alkylation, positional scanning and iterative synthetic and screening technologies.

Abstract: The instant invention is directed to a single, selectively N-alkylated compound and libraries of such compounds as set forth in Formula I. Furthermore, the instant invention is directed to methods of effecting analgesia, a decrease in the postprandial rise in the blood glucose levels of a mammal after ingestion of a carbohydrate load by said mammal, and treating microbial infections, utilizing such a single compound of Formula I in conjunction with a pharmaceutically-acceptable carrier. Also, the instant invention is directed to methods for selective alkylation, positional scanning and iterative synthetic and screening technologies.

Abstract: A process, as a substitute for hydrolysis, for preparing a nitroguanidine derivative represented by the following formula (2): ##STR1## wherein A represents a substituted or unsubstituted aromatic or non-aromatic hydrocarbon ring, a substituted or unsubstituted aromatic or non-aromatic heterocycle, a hydrogen atom or a substituted or unsubstituted alkyl, alkenyl or alkynyl group; and R.sub.2 represents a hydrogen atom, a substituted or unsubstituted C.sub.1-6 alkyl, alkenyl or alkynyl group, which comprises reacting a compound represented by the following formula (1): ##STR2## wherein R.sub.1 represents a substituted or unsubstituted, linear or cyclic C.sub.1-10 alkyl group and A and R.sub.2 have the same meanings as defined above, with ammonia, a primary amine or a secondary amine, or a salt thereof.

Abstract: The invention relates to the use of agmatine, in the treatment of acute neurotrauma (such as stroke) and degenerative disorders of the central and peripheral nervous system (such as dementia).The invention further provides novel compounds of general formula I (which are quinuclidine derivatives), formula II (which are norbornane derivatives), formula III (which are adamantane derivatives), and formula IV (which are phenothiazine derivatives): ##STR1## wherein R.sub.1, R.sub.2 and R.sub.3 are each independently hydrogen, hydroxy, substituted or unsubstituted C.sub.1-4 alkyl, substituted or unsubstituted C.sub.1-4 alkoxy, halogeno, amino, phenyl, or R.sub.4 NR.sub.5 ; R.sub.4 and R.sub.5 are each independently hydrogen, or (CH.sub.2)n--[NH(CH.sub.2)x]y--NHR.sub.6, or (CH.sub.2)n--[NH(CH.sub.2)x]y--NH--NHR.sub.6, or (CH.sub.2)n--[NH(CH.sub.2)x]y--(NR.sub.7 .dbd.)CNHR.sub.6, or (CH.sub.2)n--[NH(CH.sub.2)x]y--NH(NR.sub.7 .dbd.)CNHR.sub.6 wherein n is from 0-5, y is from 0-5 and each x is independently from 1-5; R.

Abstract: Benzoylguanidines of formula I ##STR1## with R(1) to R(4) as defined in the specification, are suitable as antiarrhythmic pharmaceuticals having a cardioprotective component for infarct prophylaxis and infarct treatment as well as for the treatment of angina pectoris.They inhibit, in a preventive manner, the pathophysiological processes in the formation of ischemically induced damage, in particular in the elicitation of ischemically induced cardiac arrhythmias.

Abstract: The present invention provides therapeutically useful substituted guanidines and methods of treatment and pharmaceutical compositions that utilize or comprise one or more of such guanidines.

Abstract: Acyl guanidines are provided which are sodium/proton exchange (NHE) inhibitors which have the structure ##STR1## wherein n is 1 to 5; X is N or C--R.sup.5 wherein R.sup.5 is H, halo, alkenyl, alkynyl, alkoxy, alkyl, aryl or heteroaryl; and R.sup.1, R.sup.2, R.sup.3 and R.sup.4 are as defined herein, and where X is N, R.sup.1 is preferably aryl or heteroaryl, and are useful as antianginal and cardioprotective agents. In addition, a method is provided for preventing or treating angina pectoris, cardiac dysfunction, myocardial necrosis, and arrhythmia employing the above acyl guanidines.

Abstract: There are described benzoylguanidines of the formula I ##STR1## having the definitions of R(1) to R(4) indicated in the text, and their pharmaceutically tolerable salts. They are obtained by reaction of a compound II ##STR2## with guanidine. They are outstanding agents for the treatment of disorders of the cardiovascular system.

Abstract: The present invention provides therapeutically useful substituted guanidines and methods of treatment and pharmaceutical compositions that utilize or comprise one or more of such guanidines.

Abstract: The present invention provides therapeutically useful substituted guanidines and methods of treatment and pharmaceutical compositions that utilize or comprise one or more of such guanidines.

Abstract: Compounds of the formula I ##STR1## are described in which at least one of the substituents R(1), R(2), R(3), R(4) and R(5) is a nitrogen-containing heterocyclic radical. They are outstanding cardiovascular therapeutic agents. They are obtained by reaction of a compound II ##STR2## with guanidine.

Abstract: Benzoylguanidines of the formula I ##STR1## in which R(1) to R(6) have the meanings stated in the claims, are antiarrhythmic pharmaceuticals which have excellent activity and a cardioprotective component and are highly suitable for the prophylaxis of infarcts and the treatment of infarcts, and for the treatment of angina pectoris, in which case they also preventively inhibit or greatly reduce the pathophysiological processes in the development of ischemia-induced damage, especially in the triggering of ischemia-induced cardiac arrhythmias.

Abstract: The present invention provides N,N'-diaryl substituted guanidines having therapeutic utility. The compounds of the present invention are represented by the formula: ##STR1## wherein R and R.sup.1 represent hydrogen or other group and Ar and Ar.sup.1 represent selected aryl groups, and at least one being acenaphthyl.

Abstract: There is disclosed a novel amino alcohol amine derivatives of L-N.sup.6 -(1-iminoethyl)lysine, pharmaceutical compositions containing these novel compounds, and to their use in therapy, in particular their use as nitric oxide synthase inhibitors.

Abstract: Arylbenzoylguanidines of the formula I ##STR1## in which R.sup.1 R.sup.2, R.sup.3 and Ph have the given meanings herein, and also the physiologically harmless salts thereof, exhibit antiarrhythmic properties and act as inhibitors of the cellular Na.sup.+ /H.sup.+ antiporter.

Abstract: Tri- and tetra-substituted guanidines which exhibit a high binding affinity to phencyclidine (PCP) receptors and, more preferably, low affinity to the brain sigma receptors. These guanidine derivatives act as non-competitive inhibitors of glutamate induced responses of the NMDA receptor by acting as blockers for the ion channel of the NMDA receptor-ion channel complex. These compounds thus exert neuroprotective activity and are useful in the therapeutic treatment of neuronal loss in hypoxia, hypoglycemia, brain or spinal cord ischemia, and brain or spinal chord trauma as well as being useful for the treatment of epilepsy, Alzheimer's disease, Amyotrophic Lateral Sclerosis, Parkinson's disease, Huntington's disease, Down's Syndrome, Korsakoff's disease and other neurodegenerative disorders.

Abstract: Compounds of the formula: ##STR1## wherein R.sup.1 --R.sup.4, R.sup.7 --R.sup.8, R.sup.a, R.sup.b, R.sup.c, Y, Z, n and m are set forth in the specification, as well as hydrates, solvates or pharmaceutically acceptable salts thereof, that inhibit a number of proteolytic enzymes are described. Also described are methods for preparing the compounds of Formula I.

Abstract: The invention relates to diaryl antimicrobial compounds of the general formula: ##STR1## where G, E L, J, q, m, X, Ar, W, p, n and A are as described herein, pharmaceutical compositions containing the compounds, methods for their production and their use in treating bacterial infections.

Abstract: Tri- and tetra-substituted guanidines which exhibit a high binding affinity to phencyclidine (PCP) receptors and, more preferably, low affinity to the brain sigma receptors. These guanidine derivatives act as non-competitive inhibitors of glutamate induced responses of the NMDA receptor by acting as blockers for the ion channel of the NMDA receptor-ion channel complex. These compounds thus exert neuroprotective activity and are useful in the therapeutic treatment of neuronal loss in hypoxia, hypoglycemia, brain or spinal cord ischemia, and brain or spinal chord trauma as well as being useful for the treatment of epilepsy, Alzheimer's disease, Amyotrophic Lateral Sclerosis, Parkinson's disease, Huntington's disease, Down's Syndrome, Korsakoff's disease and other neurodegenerative disorders.

Abstract: Substituted benzyloxycarbonylguanidines, a process for their preparation, their use as a medicament or diagnostic, and a medicament containing them. There are described compounds of the formula I ##STR1## in which the substituents R(1) to R(7) and X have the meanings shown in the claims, and their pharmaceutically tolerable salts. These are effective inhibitors of the cellular sodium proton antiporter (Na.sup.+ /H.sup.+ exchanger). They are therefore outstandingly suitable for the treatment of all diseases which can be attributed to increased Na.sup.+ /H.sup.+ exchange.

Abstract: The invention relates to cyclohexenyl antibacterial compounds of the formula I: ##STR1## and pharmaceutical compositions containing the compounds, methods for their production and use.

Abstract: 4-Aminobenzoylguanidines of the formula I ##STR1## in which A, R.sub.1, R.sub.2 and R.sub.3 have the meanings given, and the physiologically unobjectionable salts thereof exhibit antiarrhythmic properties and are active as inhibitors of the cellular Na.sup.+ /H.sup.+ antiporter.

Abstract: Indenoylguanidines of formula I and formula II, the process for their preparation, their use as medicaments, medicaments containing them, their use as diagnostic agents and medicaments containing them are described. Compounds I are useful for treating cardiac arrhythmias. Further they are useful as cardioprotective agents in mammals, which comprises administering the compound of formula-I or II with the above properties in combination with pharmaceutically accepted carrier to said mammal.

Abstract: A guanidine derivative represented by formula (1), (2), (3) or its acid addition salt and a production process thereof ##STR1## wherein each of A and B is a C.sub.2 -C.sub.8 alkylene, D is a single bond, --CO-- or a C.sub.1 -C.sub.5 alkylene, E is H, a lower alkyl or the like, m is 1 to 6, n is 0 to 6 and R.sup.1 is H, a lower alkyl or the like, l is 1 to 10 and G is H, --OH or the like and a skin cosmetic containing the same. It can exert excellent keratin layer softening effect continuously for a long period of time.

Abstract: Guanidine derivatives are provided useful for promoting growth, repair and regeneration of a neuronal axon and for treating neuropathies and myopathies. The compounds have the formula: ##STR1## wherein R.sub.1 is an isopropyl radical, a benzyl radical which is optionally substituted by one or more (C.sub.1 -C.sub.6)alkoxy radicals or a radical: ##STR2## R.sub.2, R.sub.3 and R.sub.

Abstract: The present invention is the novel synthesis of sterically hindered penta-substituted guanidines by a process in which (1a) an isocyanate is reacted first with a di-substituted amine or (1b) a urea is reacted with two moles of a mono-substituted amine to form a tri-substituted urea followed by (2) treatment of the tri-substituted urea with an activating agent before reacting with a second di-substituted amine in the presence of a base.

Abstract: A compound having the formula ##STR1## or a pharmaceutically acceptable salt thereof, whereinX, Z, Y, A, D, E, F, R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.11, R.sup.12 have the meanings set forth in the specification, pharmaceutical compositions comprising the same, and a method of treating therewith.The compounds are useful as potassium channel openers.

Abstract: 3,4,5-Substituted benzoylguanidines, process for their preparation, their use as a medicament or diagnostic and medicament containing themBenzoylguanidines of the formula I ##STR1## where R(1) is R(4)--SO.sub.m or R(5)R(6)N--SO.sub.2 --, where R(4) and R(5) are alk(en)yl, --C.sub.n H.sub.2n --R(7), and where R(7) is cycloalkyl or phenyl, where R(5) is also H, R(6) is H or C.sub.1 --C.sub.4 --alkyl,R(2) is hydrogen, (cyclo)-alk(en)(yn)yl, aryl and hetaryl,R(3) is defined as R(2)and their pharmaceutically tolerable salts are described.

Abstract: There are described benzoylguanidines of the formula I ##STR1## where R(1) is hydrogen, Hal, --NO.sub.2, --CN, --CF.sub.3, R(4)--SO.sub.m or R(5)R(6)N--SO.sub.2 --, where m is zero to 2, R(4) and R(5) are alk(en)yl or --C.sub.n H.sub.2n --R(7), n is zero to 4, where R(5) also has the meaning of H,R(6) is H or (C.sub.1 -C.sub.4)-alkyl, where R(5) and R(6) together can be 4 or 5 methylene groups,R(2) is --SR(10), --OR(10), --NRH(10), --NR(10)R(11), --CHR(10)R(12), ##STR2## where R(10) and R(11) are identical or different and are--?CHR(16)!.sub.s --(CH.sub.2).sub.p --(CHOH).sub.q --(CH.sub.2).sub.r --(CH.sub.2 OH).sub.t --R(21) or --(CH.sub.2).sub.p --O--(CH.sub.2 --CH.sub.2 O).sub.q --R(21)R(12) and R(13) are hydrogen or alkyl or, together with the carbon atom carrying them, form a cycloalkyl,R(14) is H, (cyclo)alkyl or --C.sub.n H.sub.2n --R(15),R(3) is defined as R(1), or is alkyl, hydrogen or --X--R(22) where X is oxygen, S or NR(16),and their pharmaceutically tolerable salts.

Abstract: A compound of general formula I ##STR1## wherein n is 1 or 2; R.sub.1 and R.sub.2 are each independently hydrogen, hydroxy, substituted or unsubstituted C.sub.1-4 alkyl, substituted or unsubstituted C.sub.1-4 alkoxy or halogeno;R.sub.5 is hydrogen, substituted or unsubstituted C.sub.1-4 alkyl, amino or NR.sub.6 R.sub.7 ;R.sub.3, R.sub.4, R.sub.6 and R.sub.7 are each independently hydrogen or (CH.sub.2).sub.m --[NH(CH.sub.2).sub.x ].sub.y --NHR.sub.11 wherein m is from 0-5, y is from 0-5 and each x is independently from 1-5 and R.sub.11 is hydrogen or C(NH)NH.sub.2 ;provided that when R.sub.3 and R.sub.4 are both hydrogen, R.sub.5 is amino or NR.sub.6 R.sub.7 ; pharmaceutically acceptable salts and optically active isomers thereof.

Abstract: The invention relates to triphenylalkyl antibacterial compounds of the general formula: ##STR1## pharmaceutical compositions containing the compounds, and methods for their production and use. These compounds are effective in inhibiting the action of a bacterial histidine protein kinase and are thus useful as anti-infective agents against a variety of bacterial organisms, including organisms which are resistant to other known antibiotics.

Abstract: Tri- and tetra-substituted guanidines which exhibit a high binding affinity to phencyclidine (PCP) receptors and, more preferably, low affinity to the brain sigma receptors. These guanidine derivatives act as non-competitive inhibitors of glutamate induced responses of the NMDA receptor by acting as blockers for the ion channel of the NMDA receptor-ion channel complex. These compounds thus exert neuroprotective activity and are useful in the therapeutic treatment of neuronal loss in hypoxia, hypoglycemia, brain or spinal cord ischemia, and brain or spinal chord trauma as well as being useful for the treatment of epilepsy, Alzheimer's disease, Amyotrophic Lateral Sclerosis, Parkinson's disease, Huntington's disease, Down's Syndrome, Korsakoff's disease and other neurodegenerative disorders.

Abstract: The invention provides fungicidal compounds having the general formula:X.sub.1 -A.sub.1 -B.sub.1 -C-B.sub.2 -A.sub.2 -X.sub.2 (I)wherein X.sub.1 is an amidine, a guanidine, or an imidazole group.A.sub.1 is either a five-membered aromatic ring, a six-membered aromatic ring, a fusion of two five-membered aromatic rings, a fusion of 2 six-membered aromatic rings, or a fusion of a six-membered aromatic ring and a five-membered aromatic ring;B.sub.1 is either O (oxygen) or absent; C is a straight chain alkyl comprising 1-8 carbons; B.sub.2 is either O (oxygen) or absent; A.sub.2 is either a five-membered aromatic ring, a six-membered aromatic ring, a fusion of two five-membered aromatic rings, a fusion of 2 six-membered aromatic rings, or a fusion of a six-membered aromatic ring and a five-membered aromatic ring; and X.sub.2 is an amidine, a guanidine, or an imidazole.

Abstract: The invention provides fungicidal compounds having the general formula:X.sub.1 -A.sub.1 -B.sub.1 -C-B.sub.2 -A.sub.2 -X.sub.2 (I)wherein X.sub.1 is an amidine, a guanidine, or an imidazole group.A.sub.1 is either a five-membered aromatic ring, a six-membered aromatic ring, a fusion of two five-membered aromatic rings, a fusion of 2 six-membered aromatic rings, or a fusion of a six-membered aromatic ring and a five-membered aromatic ring;B.sub.1 is either O (oxygen) or absent; C is a straight chain alkyl comprising 1-8 carbons; B.sub.2 is either O (oxygen) or absent; A.sub.2 is either a five-membered aromatic ring, a six-membered aromatic ring, a fusion of two five-membered aromatic rings, a fusion of 2 six-membered aromatic rings, or a fusion of a six-membered aromatic ring and a five-membered aromatic ring; and X.sub.2 is an amidine, a guanidine, or an imidazole.