No abstract

NotizenHeterocyclic P-Enamino Esters, 39l' Synthesis of lH-Pyrazolo[3,4-d]pyrimidinesHeterocyclische P-Enaminoester, 39'). -Synthesen von 1 H-Pyrazolo[3,4-d]pyrimidinen Die Pyrazol-Enaminoester 1 a, b und 4-Pyrazolcarbohydrazide 4a, b sind nutzliche Ausgangsverbindungen fur die Darstellung von 1 H-Pyrazolo[3,4-d]pyrimidinen. So ergeben Orthoameisensiiure-und Orthoessigsaure-triethylestcr mit 4a, b die 5-(Ethoxymethylenamino)-1 N-pyrazolo[3,4-d]pyrimidine 6a, b bzw. 11 a, b (mit 4b entsteht zusatzlich das Nebenprodukt 10). Wciterhin entstehen die 5-Amino-lH-pyrdzolo[3,4-d]pyrimidine 13a, b aus 1 a, b und Orthoameisensaure-triethylester (-+ 12a, b) und Hydrazin-hydrat. Entsprechend werden 4a, b mit Ameisensaure in die 5-Formylamino-1H-pyrazolo[3,4-d]pyrimidine 14a, b und mit Harnstoff in Decalin in die Bicyclen Ma, b umgewandelt. Erhitzen ohne Solvens liefert die 1 -(4-Pyrazolyl)semicarbazide 17a, b.

Condensation of carbohydrazide derivatives Ia, b with dimethyl acetylenedicarboxylate and acetylenedicarboxylic acid yielded benzofuran derivatives II a‐d. Reaction of Ib with aromatic aldehydes formed products III a‐d. Treatment of compounds III a‐d with mercaptoacetic acid yielded the cyclocondensation products (IVa‐d). Phthalic anhydride reacted with compounds (Ia, b)to form products (Va, b). It has been found that both khellin and visnagin (VIa, b)react with aromatic aldehydes to give arylidene derivatives (VIIa‐e). Condensation of diphenyl nitrilamine with 2‐arylidene furochromones VII derivatives afforded cyclo‐adducts (VIII a‐i). The antibacterial activities of the selected compounds were tested against Staphylococcus aureus, B. subtilis, E. coli, Pseudomonas, Salmonella and Erwinia with good results.

2-Amino-4,5,6,7-tetrahydrobenzo[b]thiophene-3-carboxamide (1) condensed with carbaldehydes 2a,b to give the respective thienopyrimidines (3a,b), which reacted with phosphoryl chloride and hydrazine hydrate to afford the respective pyrimidinohydrazines (4a,b). Compound 4a condensed with acetophenone under Vilsmeier conditions to afford the formylated pyrazolopyrimidine 6. Condensation of 4a with active methylenes produced the respective pyrazolopyrimidines (7-11). Besides, 4a condensed with succinic anhydride and with phthalic anhydride, yielding the pyrrolidine-2,5-dione 12 and the isoindoline-1,3-dione 13, respectively. Moreover, 4a reacted with isatin to afford the hydrazono-indolin-2-one 14. Structural elucidations for the new thienopyrimidines were based upon compatible analytical and spectroscopic results. Eleven of the new compounds were tested and found active against influenza A neuraminidase virus (H3N2). Compounds 12 and 13 were the most potent.

No abstract