Abstract: Disclosed is a novel peptide having one of the formulae: ##STR1## (A and B are the amino acids: wherein if A is D- or L-Pro, B is Hat or Cit;if A is D-Pro, B is D-Arg, andif B is D- or L-Arg, A is Sat, Pip, Aze or Arg)Asn-A-L- (D-)Pro-Arg- (Gly)n (A is Set, Thr or Ala, n is 1 or 0)A-Ser-Pip-Arg (A is Pro-Asn-, Asn- or Pro-) ##STR2## (A is cyclopentylcarbonyl, Pro or pGlu; B is Gly or .beta.-Ala, W is a hydrogen atom or a group having the formula:or a peptide having the formula: ##STR3## wherein A and B have the same meanings as mentioned above, respectively pGlu-Asn-Ser-A-B-(Gly)n (A is Aze, D- or L-Pro, Pip or Sat, B is D- or L-Arg, Cit, Hat, Lys or Orn, n is 1 or 0) andPro- (Ash)m-Set-L- (D-)Pro-Arg- (Gly) n (m and n are independently 0 or 1)their functional derivatives, and pharmaceutically acceptable salts thereof.

Abstract: A novel peptide derivative having the formula: ##STR1## wherein A between Pro and Q.sup.2 is Arg or Lys: Q.sup.1 is pGlu or H; Q.sup.2 is --Gly--OH or OH; Y.sup.1 is H or --CO--T and Y.sup.2 is OH or T; wherein T is a thiamine derivative group is disclosed. The peptide derivative shows a remarkable nootropic effect.

Abstract: A peptide having one of the following formulae (I), (II), (III) and (IV): ##STR1## or its functional derivatives, and a pharmaceutically acceptable salt thereof are disclosed. These peptides have a nootropic effect and are effective as antidementia agents.

Abstract: Disclosed is a novel peptide having one of the formulae: ##STR1## (A and B are the amino acids: wherein if A is D- or L-Pro, B is Har or Cit;if A is D-Pro, B is D-Arg, andif B is D- or L-Arg, A is Sar, Pip, Aze or Arg)Asn-A-L-(D-)Pro-Arg-(Gly).sub.n(A is Ser, Thr or Ala, n is 1 or 0)A-Ser-Pip-Arg(A is Pro-Asn-, Asn- or Pro-) ##STR2## (A is cyclopentylcarbonyl, Pro or pGlu; B is Gly or .beta.-Ala, W is a hydrogen atom or a group having the formula: or a peptide having the formula: ##STR3## wherein A and B have the same meanings as mentioned above, respectivelypGlu-Asn-Ser-A-B-(Gly).sub.n(A is Aze, D- or L-Pro, Pip or Sar, B is D- or L-Arg, Cit, Har, Lys or Orn, n is 1 or 0) andPro-(Asn).sub.m -Ser-L-(D-)Pro-Arg-(Gly).sub.n(m and n are independently 0 or 1)their functional derivatives, and pharmaceutically acceptable salts thereof.

Abstract: The compounds of the formulas (VI) and (VII) are useful intermediates in producing pyridyloxy derivatives of the formula (I), such as, for instance, N-{4-[4-(piperidinomethyl)pyridyl-2-oxy]-2-butenyl}-2-(furfurylt hio)acetamide, which are useful as anti-peptic ulcer agents. The compounds of formula (VI) have the formula ##STR1## wherein A represents a formyl group, a protected formyl group, a hydroxymethyl group or a protected hydroxymethyl group. The compounds of formula (VIII) have the formula ##STR2## wherein G represents a formyl group, a protected formyl group, a hydroxymethyl group, a hydroxymethyl group in which the hydroxyl group is protected, or a halogenomethyl group, Y represents --CH.sub.2 --CH.sub.2 -- or --CH.dbd.CH--, and n is 0, 1 or 2.

Abstract: A compound represented by the following formula or a salt thereof ##STR1## wherein each of R.sub.1 and R.sub.2 represents a lower alkyl group, or R.sub.1 and R.sub.2, together with the nitrogen atom to which they are bonded, may form a substituted or unsubstituted, saturated or partially unsaturated 4- to 8-membered heterocyclic group which may contain a hetero atom selected from N, O and S, Y represents a group of the formula --CH.sub.2 --CH.sub.2 -- or --CH.dbd.CH--, and n is 0, 1 or 2. This compound is useful as anti-peptic ulcer agent.

Abstract: Alkylamide derivatives having the formula, These compounds have a strong antiulcer action depend on histamine H.sub.2 -receptor antagonistic action and a cytoprotective action upon gastric mucous membrance.

Abstract: Addition compounds have the formula ##STR1## wherein R.sub.1 represents an aliphatic oxycarbonyl group, benzyloxycarbonyl group which can have nuclear substituents or benzoyl, aromatic sulfonyl or aromatic sulfinyl group; R.sub.2 represents methyl, isopropyl, isobutyl, isoamyl or benzyl group; R.sub.3 represents a lower alkoxyl, benzyloxy or benzhydryloxy group and n represents 1 or 2.The addition compounds are produced by reacting an N-substituted monoaminodicarboxylic acid having the formula ##STR2## with an amino carboxlic acid ester having the formula in an aqueous medium in the presence of a protease and reacting the resulting dipeptide ester with the amino carboxylic acid ester and separating the addition compound.The addition compounds can be decomposed into the constituent dipeptide esters and amino acid esters by the action of an acid.

Abstract: Addition compounds having the formula ##STR1## wherein R.sub.1 represents an aliphatic oxycarbonyl group, benzyloxycarbonyl group which can have nuclear substituents, or benzoyl, aromatic sulfonyl or aromatic sulfinyl group; R.sub.2 represents methyl, isopropyl, isobutyl, isoamyl or benzyl group; R.sub.3 represents a lower alkoxyl, benzyloxy or benzhydryloxy group and n represents 1 or 2 are produced by reacting an N-substituted monoaminodicarboxylic acid having the formula ##STR2## with an amino carboxylic acid ester having the formula ##STR3## in the presence of a protease.

Abstract: Addition compounds having the formula ##STR1## wherein R.sub.1 represents an aliphatic oxycarbonyl group, benzyloxycarbonyl group which can have nuclear substituents, or benzoyl, aromatic sulfonyl or aromatic sulfinyl group; R.sub.2 represents methyl, isopropyl, isobutyl, isoamyl or benzyl group; R.sub.3 represents a lower alkoxyl, benzyloxy or benzhydryloxy group and n represents 1 or 2 together with methods for preparing (I) and for decomposing (I) into the constituent dipeptide esters and amino acid esters.

Abstract: A peptide having the formulaX--A--B--Ywherein A and B are the same or different and represent an amino acid residue or a peptide residue; X represents an amino protective group and Y represents a carboxyl protective group, is prepared by reacting an amino acid or peptide having an N-terminal protective group or a salt thereof of the formula:X--A--OHwith an amino acid or peptide having a C-terminal protective group or a salt thereof of the formula:H--B--Yin the presence of metalloproteinase in an aqueous solution having a pH which maintains the enzyme activity of said metalloproteinase.

Abstract: A peptide having the formulaX--A--B--Ywherein A and B are the same or different and represent an amino acid residue or a peptide residue; X represents an amino protective group and Y represents a carboxyl protective group, is prepared by reacting an amino acid or peptide having an N-terminal protective group or a salt thereof of the formula:X--A--OHwith an amino acid or peptide having a C-terminal protective group or a salt thereof of the formula:H--B--Yin the presence of metalloproteinase in an aqueous solution having a pH which maintains the enzyme activity of said metalloproteinase.

Abstract: A peptide having the formulaX--A--B--Y--wherein A and B are the same or different and each represents an amino acid residue or a peptide residue, X represents an amino protective group, Y represents a carboxyl protective group selected from the group consisting of tertiary alkoxy, and benzyloxy, benzylamino and benzhydrylamino which can be substituted with an inert substituent, is prepared by a process which comprises reacting an amino acid or peptide having an N-terminal protective group, or a salt thereof of the formula:X--A--OHwith an amino acid or peptide having a C-terminal protective group or a salt thereof of the formula:H--B--Yin the presence of a thiol proteinase or serine proteinase enzyme in an aqueous solution having a pH sufficient to maintain the enzyme activity of said thiol proteinase or serine proteinase.

Abstract: A novel process for producing an N-alkylhydroxylamine of the formula (I)rnh-oh (i)wherein R represents an alkyl group which may be substituted with least one substituent, which comprises reacting an N-mesyl-O-(p-alkoxybenzyl)hydroxylamine or an N-mesyl-O-(2,4,6-trialkylbenzyl)hydroxylamine with an alkyl halide of the formula (III)rx (iii)wherein R is as defined above and X represents a halogen atom, under a basic condition to produce the corresponding N-alkyl-N-mesyl-O-(p-alkoxybenzyl)hydroxylamine or N-alkyl-N-mesyl-O-(2,4,6-trialkylbenzyl)hydroxylamine, and treating the resulting compound with a solution of a phenol compound, and novel N-alkyl-N-mesyl-O-(p-alkoxybenzyl)hydroxyl amines and N-alkyl-N-mesyl-O-(2,4,6-trialkylbenzyl)hydroxylamines which are useful as intermediates in the above process.

Abstract: A peptide having the formula:X-A-B-C-YwhereinA represents Ala., Gln., Asn., .omega.-BOC-Lys., Leu., Gly., Glu., ##EQU1## OR A represents A.sub.1 -- A.sub.2 wherein A.sub.1 represents a hydrophilic amino acid residue and A.sub.2 represents Val., Met., Leu. or Gln.;B represents Phe., Tyr., Leu., Met., Glu., Asp., Gln., Asn or Trp.;C represents Phe., Leu., Ileu., Try., Cys-SBzl., Ser-OBzl., Trp. or Met.;X represents an .alpha.-amino acid protective group; an amino acid residue having an N-terminal protective group or a peptide residue having an N-terminal protective group; Y represents a carboxyl protective group, an amino acid residue having a C-terminal protective group or a peptide residue having a C-terminal group, is produced in a process which comprises reacting a peptide having the formulaX-A-B-OHwith an amino acid or a peptide having the formulaH-C-Yin the presence of enzyme pepsin.