Derivatives of arborine [1-methyl-2-(phenylmethyl)-4(1H)-quinazolinone]

Positional isomers of thienopyrimidinones

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We have shown previously that derivatives of 4-oxo-2-quinazolinylmethylbenzoic acids are formed by the reaction of o-cyanomethylbenzoic acid (1) with anthranilic [1] and N-methylanthranilic acids [2]. In a continuation of this work we have used in the condensation with acid 1 any derivatives of vicinal enaminoacids -esters of isomeric amino acids of the thiophene series.

It was established that boiling a chlorobenzene solution of acid 1 with 2 equivalents of the esters of the amino acids 2 or 3 for 10 min gave derivatives of thienopyrimidinones 4 and 5 in yields of not less than 70% (Table 1).

The yields of the required products were halved when equivalent amounts of the reagents were used.

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“…We have shown previously that derivatives of 4-oxo-2-quinazolinylmethylbenzoic acids are formed by the reaction of o-cyanomethylbenzoic acid (1) with anthranilic [1] and N-methylanthranilic acids [2]. In a continuation of this work we have used in the condensation with acid 1 any derivatives of vicinal enaminoacids -esters of isomeric amino acids of the thiophene series.…”

Synthesis of substituted 4-oxo-3,4-dihydro-thieno[3,4-d]pyrimidines and comparison of their properties with those of positionally isomeric thienopyrimidinones and benzo isosteres

“…It was shown previously that alkylation at atom N(1) led to a shift of the carbonyl stretching vibration to 1630 cm -1 , whereas the alternative alkylation at atom N(3) led to a shift to 1655-1660 cm -1 [11]. In the infrared spectrum of compound 6A the band discussed was found at 1686 cm -1 (see Table 1).…”

“…Starting from 2-cyanomethylbenzoic acid (1) and methyl 3-amino-4-thiophenecarboxylate we have synthesized compounds of types 3-6 of system A (series A) by the scheme shown below -these are analogs of the derivatives of systems B, C, and D which we prepared previously: 3B-6B, 3C-6C [1], and 3D-6D [10,11]. In connection with the known instability of the amino ester starting material [12], the latter was obtained in situ from its hydrochloride 2 by adding to the reaction mixture the calculated amount of Et 3 N. The proposed new method allowed the yield of product 3A to increase to 90%.…”

“…In connection with the known instability of the amino ester starting material [12], the latter was obtained in situ from its hydrochloride 2 by adding to the reaction mixture the calculated amount of Et 3 N. The proposed new method allowed the yield of product 3A to increase to 90%. For the others the conditions for obtaining derivatives 3-6 of series A were analogous to those we described previously for the synthesis of compounds 3-6 of series B-D [1, 10,11].…”