Abstract
2-Thiothymine (I) undergoes S-alkylation when treated with some halo compounds such as methyl and ethyl iodides. The S-alkyl derivatives II are treated with hydrazine hydrate to produce the hydrazine derivative III , which condensed with p-chlorobenzaldehyde to give p-chlorobenzaldehydepyrimidinehydrazone derivative IV . Compound II a reacts with phosphorus oxychloride to give 4-chloro derivative V . The chlorine atom in V undergoes nucleophilic substitution with p-chloroaniline and anthranilic acid to produce drivatives VI a,b . Dehydrative cyclization of VI b yields the pyrimido[6,1-b]quinazolin-10-one derivative VII . Treatment of V with ammonia solution gives the diamino derivative VI d . Reaction of V with sodium azide produces the tetrazolo[1,5-c]pyrimidine derivative VIII . Compound I undergoes S-alkylation with f -haloketones followed by cyclization to produce the thiazolo[3,2-a]pyrimidine derivatives X a-c . Reaction of I with bromomalononitrile produces thiazolo[3,2-a]pyrimidine-2-carbonitrile derivative XII . Treatment of XII with formic acid, formamide and ammonium thiocyanate produces thiazolo[3,2-a:4,5-d]dipyrimidine derivatives XIII a-c . Finally, reacting XII with malononitrile yields ppyrido[2',3':4,5]thiazolo[3,2-a]pyrimidine-3-carbonitrile derivative XIV .