Ring Opening and Recyclization Reactions with Chromone‐3‐carbonitrile

Abstract

Chemical transformations of chromone‐3‐carbonitrile (1) with some substituted hydrazines, namely, thiosemicarbazide, S‐methyl/benzyldithiocarbazate, 7‐chloro‐4‐hydrazinoquinoline, and 3‐hydrazino‐5,6‐diphenyl‐1,2,4‐triazine, led to substituted pyrazoles 2, 5–8. Ring opening of carbonitrile 1 followed by recyclization with 3‐amino‐1,2,4‐triazole and 2‐aminobenzimidazole gave triazolo[1,5‐a]pyrimidine 9 and pyrimido[1,2‐a]benzimidazole 10, respectively. Treatment of carbonitrile 1 with some heterocyclic amines produced 2‐amino‐3‐substituted‐chromones 11 and 12. The novel 3‐hydroxychromeno[4,3‐b]pyrazolo[4,3‐e]pyridin‐5(1H)‐one (13) was efficiently synthesized from the ring conversion of carbonitrile 1 with cyanoacetohydrazide. A mixture of chromeno[2,3‐b]naphthyridine 14 and chromeno[4,3‐b]pyridine 15 was obtained from base catalyzed transformation of carbonitrile 1 with malononitrile dimer. A diversity of novel annulated chromeno[2,3‐b]pyridines 16–22 was also synthesized. Chromeno[2,3‐b]pyrrole‐2‐carboxylate 23 was obtained from the reaction of carbonitrile 1 with ethyl chloroacetate. Structures of the new synthesized products were deduced on the basis of their analytical and spectral data.

Synthesis and antimicrobial evaluation of the novel heteroannulated furo[3′,2′:6,7]chromeno[2,3‐b]pyridines: Part 1

“…In the same manner, the linear heteroannulated hexafused furo[3′,2′:6,7]chromeno[2,3‐ b ]indeno[2,1‐ e ]pyridine derivative 7 was synthesized by reacting carbonitrile 1 with 1,3‐indanedione in absolute ethanol (Scheme 3). [ 30 ] The IR spectrum of compound 7 showed distinctive absorption bands at 1720 (CO indanone ), 1661 (CO γ‐pyrone ), and 1612 cm −1 (CN). Its 1 H NMR spectrum showed specific singlet at δ 8.57 assigned to H‐4 pyridine .…”

“…Also, the novel furo[3″,2″:6′,7′]chromeno[3′,2′:5,6]pyrido[2,3‐ d ]pyrimidines 10 and 11 were efficiently prepared from base catalyzed ring opening ring closure reactions of carbonitrile 1 with barbituric acid and 1‐allylthiobarbituric acid, respectively (Scheme 5). [ 30 ] The IR spectra of compounds 10 and 11 showed specific absorption bands at 1692/1707 and 1656/1649 cm −1 assigned to CO pyrimidinone and CO γ‐pyrone , respectively. Definite singlet observed in 1 H NMR spectra of compounds 10 and 11 , attributed to H‐6 at δ 8.82 and 8.85, respectively.…”

Synthesis, FT-IR, structural, thermochemical, electronic absorption spectral, and NLO analysis of the novel 10-methoxy-10H-furo[3,2-g]chromeno[2,3-b][1,3]thiazolo[5,4-e]pyridine-2,10(3H)-dione (MFCTP): a DFT/TD-DFT study

“…Also, the structure-activity relationship (SAR) was studied for the antimicrobial application of the current compound (3,MFCTP). Mass spectrum, m/z (I r %): 340 (M + , 100), 312 (62), 296 (43), 269 (58), 191 (41), 175 (28), 169 (12), 147 (34), 123 (9), 118 (70), 107 (40), 91 (23), 77 (27), 64 (13). Anal.…”

Novel Heteroannulated Chromeno[2,3-b]pyridines and Related Compounds Using 6-Methylchromone-3-carbonitrile

“…), 1672 (C=Oamide), 1642 (C=Oγ-pyrone), 1617 (C=N), 1579 (C=C). 1 H NMR (300 MHz, DMSO-d6) δ: 0.97 (t, 3H, J=6.9 Hz, CH3), (20), 253 (100), 225 (37), 210 (18), 157 (6), 135 (52), 120 (29), 77 (17), 64 (8).…”