Novel data for the reaction of 3-cyano-(thio)chromones with N-nucleophiles

Abstract

Recent literature data for the reaction of 3-cyano(thio)chromones with amines, hydrazines, and hydroxylamine are summarized.

Overview on Developed Synthesis Methods of Triazepane Heterocycles

“…1,2,4‐Triazepane 84 was prepared from the reaction of chromone 82 with 1,6‐diamino‐4‐(4‐chlorophenyl)‐2‐oxo‐1,2‐dihydropyridine‐3,5‐dicarbonitrile 83 in DMF under reflux conditions (Scheme ) …”

Chemistry of 3-carbonyl-2-methyl-4-oxo-4H-1-benzopyrans

“…A lithium dialkynylcuprate as [(TMS-C≡C) 2 CuLi], though capable of transferring its alkynyl group in a conjugate addition to the ester 6e, failed to react with 3-alkoxycarbonyl-2-methylchromone 5. Heteroannulation of the chromone A (≡ 2, 3, 5a) with 2-chloroethanol in the presence of K 2 CO 3 to the corresponding furobenzopyranone 101 (Equation 8) proceeds via the conjugate addition of the haloethanol to the chromone followed by intramolecular alkylation.…”

“…Later Li et al 86 reported that the product 157, if prepared from 118a and 155, remains admixed with the benzothiazole 158; it can be had exclusively by treating the acid chloride 159 with the thiophenol 155 in N-methyl-2-pyrrolidone at 100 °C. A mixture of Zn(OAc) 2 and potassium salt of thiazole 157 in a molar ratio of 1:2 in MeOH-H 2 O forms the four coordinated Zn(II) complex 160. as well as with phenyltrimethylammonium tribromide 91 give the corresponding 3-bromoacetylchromones (Equation 10), the latter reagent being claimed to improve the yield.…”

“…Because of these functionalities (activated olefinic bond, electrophilicity at three centres and nucleophilicity at the 2-methyl group), the chemistry of 2-methylchromones 1-5 is more varied than that of the lower homologues 6. Of the several review articles on chromones, the latest one on 2-methylchromone 8 1 , two on the nitrile 7a 2,3 and three on 3-formylchromone 6a [4][5][6] are noteworthy. In contrast, a full, complete and up-to-date survey on the chemistry of the title chromones 1-5 is still lacking.…”

Ring Opening and Recyclization Reactions of 3‐Nitrochromone with Some Nucleophilic Reagents

“…Recently, chromone derivatives were used in diverse optoelectronic applications . Introduction of an electron‐withdrawing group into the 3‐position of chromone changes the reactivity of the γ‐pyrone ring towards nucleophilic reagents and opens up a broad synthetic scope of this important oxygen‐containing heterocyclic systems . 3‐Substituted chromones are very active substrates for nucleophilic attack at C‐2 position and used as valuable synthetic intermediates in the preparation of a variety of heterocyclic compounds .…”