Abstract: A process for preparing compounds (1) ##STR1## where Y is NR.sup.1 R.sup.2 or OR, R.sup.1 and R.sup.2 are hydrogen or C.sub.1-3 alkyl, and R is C.sub.1-3 alkyl, which comprises protecting the hydroxy group of a compound (2) ##STR2## cyclising the product under basic conditions and removing the protecting group.

Abstract: A series of chemical reactions starting from the condensation of uracil with an acid stable heterocyclic aldehyde in an acid medium produces biologically active end products which are 2-heterocyclylmethylthioethylamino-5-heterocyclylmethyl-4-pyrimidinones. The new reactions and intermediates of this invention are particularly useful for preparing 2[2-(5-dimethylaminomethyl-2-furylmethylthio)-ethylamino]-5-(6-methyl-3-py ridylmethyl)-4-pyrimidinone and its salts. This compound is a potent H.sub.2 -antagonist with a long duration of activity.

Abstract: This invention relates to 2-substituted aminopyridone compounds which have histamine H.sub.2 -antagonist activity.

Abstract: Pyridine derivatives are disclosed which are useful as histamine H.sub.1 -antagonists.

Abstract: This invention relates to 4-aminoalkyl-2-pyridyl alkylguanidines which are intermediates for pyrimidone compounds having histamine H.sub.2 -antagonist activity.

Abstract: Heterocyclic compounds which are inhibitors of histamine activity, in particular, inhibitors of H-2 histamine receptors. A specific compound of this invention is 2-[2-(4-methyl-5-imidazolymethylthio)ethylamino]-4-pyrimidone.

Abstract: 3-Nitro-2-substituted aminopyrroles are histamine H.sub.2 -receptor antagonists. The 2-position substituent is a fully-unsaturated heterocyclyl alkyl group preferably with alkyl group interrupted by sulfur or oxygen. The 4- and 5-positions of the pyrrole ring can also be substituted.

Abstract: Compounds of the formula: ##STR1## where R.sup.1 is halogen or nitro; R.sup.2 is C.sub.1-4 alkyl; and R.sup.3 is a C.sub.1-3 alkylene group are intermediates to 2-(3,5-disubstituted pyridyl-alkyl amino)-5-pyridylmethyl-4-pyrimidone derivatives which are useful as histamine H.sub.1 -antagonists.

Abstract: Heterocyclic compounds which are inhibitors of histamine activity, in particular, inhibitors of H-2 histamine receptors. A specific compound of this invention is 2-[2-(4-methyl-5-imidazolylmethylthio)ethylamino]-4-pyrimidone.

Abstract: The compounds are C.sub.2 -C.sub.8 straight chain alkanes terminally substituted, symmetrically or unsymmetrically, by N-(N'-substituted guanidino), N-(N',N"-disubstituted guanidino). N-(N'-substituted thioureido), N-(nitromethylene amidino) or S-(N-substituted isothioureido) groups. Two compounds of the invention are 1,3-bis-[N'-(2-(5-methyl-4-imidazolylmethylthio)ethyl)guanidino]propane and 1,3-bis-[S-(N-2-(5-methyl-4-imidazolylmethylthio)ethyl)isothioureido]p ropane. The compounds of this invention are inhibitors of H-2 histamine receptors.

Abstract: This invention relates to 2-pyridine derivatives substituted in the 4-position with a dialkylamino- or piperidinyl- or pyrrolidinylalkyl group. The compounds have histamine H.sub.2 -antagonist activity.

Abstract: This invention relates to cytosine derivatives which have histamine H.sub.2 -antagonist activity. A specific compound of this invention is 4-[3-(3-(piperidinomethyl)phenoxy)propylamino]-pyrimidin-2-thione.

Abstract: This invention provides a process for the preparation of pyrimidinone compounds with a group R.sup.2 CH(OH)-- at the 5-position thereof, wherein R.sup.2 is an optionally substituted acid-stable 5- or 6-membered nitrogen-containing heteroaryl group. The pyrimidinone ring is further substituted by a side-chain of a H.sub.1 -antagonist or H.sub.2 -antagonist or a precursor thereof.The compounds are convertible to 5-heteroaryl methyl compounds which are either useful H.sub.1 - or H.sub.2 -antagonists or precursors thereof.

Abstract: This invention relates to Mannich-furyl(thienyl, pyridyl or phenyl) alkylaminoimidazolinones which have histamine H.sub.2 -antagonist activity. A specific compound of this invention is 2-[2-(5-dimethylaminomethylfuran-2-ylmethylthio)-ethylamino]-1-methyl-imid azolin-4-one.

Abstract: The compounds are isoureas and isothioureas which have an O- or S- alkylpyrimidone substituent and which are histamine H.sub.2 -antagonists and antiinflammatory agents. A specific compound of this invention is 2-[5-(O-isoureido)pentylamino]-5-(6-methyl-3-pyridylmethyl)-4-pyrimidone.

Abstract: This invention relates to diaminotriazole derivatives in which one amino group is substituted by a 4-dialkylamino- or piperidinyl- or pyrolidinylmethyl pyrid-2-yloxypropyl group. The compounds have histamine H.sub.2 -antagonist activity. One specific compound is 1-methyl-N.sup.5 -3-(4-[1-piperidinomethyl]-pyridyl-2-oxy)-propyl-1H-1,2,4-triazole-3,5-dia mine.

Abstract: Pyridine derivatives are disclosed which are useful as histamine H.sub.1 -antagonists.

Abstract: This invention relates to 2-amino-3-hydroxy, and 3-carboxy pyridine derivatives, in which the amino group is substituted by a methylthioethyl, butyl or oxypropyl group bearing a terminal heterocyclic group. The compounds have histamine H.sub.2 -antagonist activity. A specific compound of this invention is 2-[2-(2-guanidino-4-thiazolylmethylthio)ethyl]amino pyridine 3-carboxylic acid.

Abstract: Pyridine derivatives are disclosed which are useful as histamine H.sub.1 -antagonists.

Abstract: This invention relates to N-substituted pyridinone compounds which have histamine H.sub.2 -antagonist activity. A specific compound of this invention is 2-[2-(5-methyl-4-imidazolylmethylthio)ethylamino]-5-(1-methyl-2-oxopyridin -4-ylmethyl)pyrimidin-4-one.