Quinazolinecarboxylic Acids. Synthesis of Alkyl-,- and (5,6,7,8-Tetrahydro-2-phenylquinazolin-4-ylthio)alkanoates

Article abstract of DOI:10.1002/hlca.19860690509

The <(2-aminobenzoyl)amino>alkanoic acids and their esters 1 showed a different reaction behaviour with diethyl oxalate.Compound 1 (n = 2,3) was converted into the quinazolinylalkanoates 3. o-Aminohippurate yielded with ethyl (chloroformyl)formate a mixture of the amide 4 and the cyclized quinazolinone 7b.Ethyl 3,4-dihydro-4-oxoquinazoline-2-carboxylate (6) reacted with 2-bromoalkanoates, in the presence of NaH, to the <2-(ethoxycarbonyl)-3,4-dihydro-4-oxoquinazolin-3-yl>acetates 7 in the case alkyl bromoacetate, and to the O-alkylated derivatives 8 with the ethyl 2-bromopropionate and -butyrate. 2-Aminobenzamide (5) gave with ethyl 3-(chloroformyl)-2-propenoate and methyl 3-(chloroformyl)propionate the amides 9 or 11, respectively, and not the expected quinazolinones.The cyclized product 12 was obtained from 11 and ethyl bromoacetate.Tetrahydroquinazolin-4(3H)-thione 14 was synthesized by the reaction of 13 with NH3, and it was alkylated at the S-atom with bromoalkanoates to 15.The hydrazide 16 was synthesized from 15b with hydrazine hydrate.