- AMIDOPYRAZOLE DERIVATIVE
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A platelet coagulation inhibitor which inhibits neither COX-1 nor COX-2 is provided. The inhibitor is a compound represented by general formula (I): wherein Ar1 and Ar2 independently represent a 5- or 6-membered aromatic heterocyclic group optionally substituted with 1 to 3 substituents, or a phenyl group optionally substituted with 1 to 3 substituents; R1 represents a lower acyl group, carboxyl group, a lower alkoxycarbonyl group, a lower alkoxy group, a lower alkyl group optionally substituted with 1 or 2 substituents, a carbamoyl group optionally substituted with 1 or 2 substituents, an oxamoyl group optionally substituted with 1 or 2 substituents, an amino group optionally substituted with 1 or 2 substituents, a 4- to 7-membered alicyclic heterocyclic group optionally substituted with 1 or 2 substituents, a phenyl group optionally substituted with 1 to 3 substituents, or a 5- or 6-membered aromatic heterocyclic group optionally substituted with 1 to 3 substituents; and R2 represents hydrogen atom, a halogeno group, or the like.
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Page/Page column 126-127
(2010/11/23)
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- Reactions of 3-(Dimethylamino)-2,2-dimethyl-2H-azirines with Barbituric-Acid Derivatives
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The reaction of 3-(dimethylamino)-2,2-dimethyl-2H-azirine (1) and 5,5-disubstituted barbituric acids 5 in i-PrOH at ca. 70 deg gives 2-alkanamides of type 6 in good yields (Scheme 1).The formation of 6 proceeds with loss of CO2; various reaction mechanisms with a zwitterionic 1:1 adduct B as common intermediate are discussed (Schemes 2 and 5).Thermolysis of product 6 leads to 2-alkyl-5-(dimethylamino)-4,4-dimethyl-4H-imidazoles 8 or the tautomeric 2-alkylidene derivatives 8'via elimination of HNCO (Scheme 3).The latter undergoes trimerization to give 1,3,5-triazine-2,4,6-trione.No reaction is observed with 1,5,5-trisubstituted barbiturates and 1 in refluxing i-PrOH, but an N-alkylation of the barbiturate occurs in the presence of morpholine (Scheme 4).This astonishing reaction is explained by a mechanism via formation of the 2-alkoxy-2-(dimethylamino)aziridinium ion H which undergoes ring opening to give the O-alkylated 2-amino-N1,N1-dimethylisobutyramide I as alkylating reagent (Scheme 4).
- Schlaepfer-Daehler, Marlise,Heimgartner, Heinz
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p. 2275 - 2286
(2007/10/02)
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