Quinazolines 1. Synthesis and chemical reactions of 6-chlorosulfonyl-quinazoline-2,4-diones

Treatment of quinazoline-2,4-dione and its symmetrical 1,3-dialkyl derivatives with chlorosulfonic acid gave the corresponding 6-chlorosulfonylquinazoline-2,4-diones. Reaction of the compounds obtained with nucleophilic agents (water, ammonia, aliphatic and cyclic amines) gave the corresponding free 2,4-dioxoquinazoline-6-sulfonic acids, 6-sulfamidoquinazoline-2,4-diones, and 2,4-dioxoquinazoline-6-sulfonic acid amides. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 420–427, March 2008.     

Quinazolines. VIII. Synthesis of 1,3-diaminobenzo[f]quinazolines

Twenty-one 1,3-diaminobenzo[f]quinazolines ( 2 , R = H, alkyl, halogen, methoxy) were synthesized as planar tricyclic analogs of the antimalarial agent pyrimethamine ( 1 ). The synthetic methods included i) condensation of 1-cyano-2-naphthylamines with cyanamide in the presence of pyridine hydrochloride, ii) cyclization of N¹,N⁵-bis(2-naphthyl)biguanide hydrochlorides in diphenyl ether at 250°, iii) reaction of 2-naphthylamine hydrochlorides with excess sodium dicyanamide in boiling 1-octanol, and iv) selenium dioxide dehydrogenation of 1,3-diamino-5,6-dihydrobenzo[f]quinazolines. A number of new 2-naphthols and 2-naphthylamines were synthesized as intermediates. Substituent effects on the ultraviolet absorption spectra of 1,3-diamino-benzo[f]quinazolines were investigated and found to be additive. These compounds are of interest as inhibitors of dihydrofolate reductase and as potential antimalarial and antitumor agents.     

Synthesis of benzo[b]selenophene and its methyl homologs

A method for the synthesis of benzo[b]selenophenes was perfected. 3-Oxo-2,3-dihydrobenzo[b]selenophene and 2-methyl-3-oxo-2,3-dihydrobenzo[b]selenophene exist only in the keto form. 3-Methylbenzo[b]selenophene was obtained by the reaction of 3-oxo-2,3-dihydrobenzo[b]selenophene with methylmagnesium iodide. Metallation of benzo[b]selenophene with butyllithium proceeds at the 2 position of the selenophene ring.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1475–1480, November, 1970.     

Synthesis of 1,2,5-trimethyl-4-ethoxycarbonylmethyl-4-hydroxypiperidine and its homologs

1,2,5-Trimethyl-4-ethoxycarbonylmethyl-4-hydroxypiperidine was obtained by the Reformatsky reaction between 1,2,5-trimethyl-4-piperidone and ethyl bromoacetate. Homologs were obtained from the same piperidone and ethyl -bromo--alkylacetates. Some further reactions of these hydroxypiperidines were studied.     

Synthesis of 6,6-disubstituted penems

The synthesis of a series of 6,6-disubstituted penems starting from penicillanate 5a is described. These penems were isolated and characterized as their pivaloyloxy methyl ester.     

Quinazolines. VII. Synthesis of 1,3-Diamino-5,6-dihydrobenzo[f]quinazolines

Eighteen new 1,3-diamino-5,6-dihydrobenzo[f] quinazolines ( 6 , R. = alkyl, Cl, MeO) were synthesized via the condensation of appropriate 2-tetralones with cyanoguanidine under fusion conditions. Methods were developed for the preparation of a number of heretofore undescribed 2-tetralones as precursors. The final products can be viewed as conformationally rigid analogs of pyrimethamine ( 2 ), and are of interest as inhibitors of dihydrofolate reductase and as potential antimalarial and antitumor agents.     

Synthesis of homologs of p-phenoxystyrene

Conclusions Homologs of p-phenoxystyrene that had not been described in the literature have been synthesized: -methyl-p-phenoxystyrene, -ethyl-p-phenoxystyrene, ,-dimethyl-p-phenoxystyrene, -methyl-p-phenoxystyrene, and ,-dimethyl-p-phenoxy styrene.     

Synthesis of homologs of pyrrole and pyrrolidine

Conclusions 1-(5-Methylfuryl)-3-aminoalkanes on vapor phase hydrogenation over Pt/C at 220–270° are converted into pyrrole and pyrrolidine homologs in 60–70% yield.Translated from. Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 1, pp. 210–213, January, 1968.