Thionyl Chloride → 4-Oxo-4H-chromene-3-carbonitrile

HRID 2048959

Reaction equation

HRID 2048959 reaction equation
O1C2C(=CC=CC=2)C(=O)C(C(O)=O)=C1.S(Cl)(Cl)=O.[O:19]1[C:28]2[C:23](=[CH:24][CH:25]=[CH:26][CH:27]=2)[C:22](=[O:29])[C:21]([C:30]([NH2:32])=O)=[CH:20]1>CN(C)C=O>[C:30]([C:21]1[C:22](=[O:29])[C:23]2[C:28](=[CH:27][CH:26]=[CH:25][CH:24]=2)[O:19][CH:20]=1)#[N:32]

Participants

5

Reactant 3

HCID 24386Thionyl Chloride2×HCID 181620Chromone-3-carboxylic acidHCID 12200777HCID 12200777, compound2×

Product 1

HCID 5212984-Oxo-4H-chromene-3-carbonitrileYield 75%

Reagents, catalysts & solvents 1

HCID 6228DimethylformamideSolvent

Procedure

The present invention concerns a novel method of preparing these 3-cyanochromones from chromone-3-carboxylic acids. The reaction mechanism of the present invention may best be described by the following reaction scheme: ##STR4## Referring to the reaction scheme, chromone-3-carboxylic acid is initially converted to the acyl chloride by treating with thionyl chloride as disclosed in U.S. Pat. No. 3,849,446 to Von Strandtmann, et al., issued Nov. 19, 1974. The acyl chloride is then converted to the corresponding chromone-3-carboxamide, as disclosed in U.S. Pat. No. 3,862,143. The critical feature of the present invention is the further dehydration of the chromone-3-carboxamide with thionyl chloride in N,N-dimethylformamide to give the desired 3-cyanochromone in a high yield of at least 75%. Generally, a molar excess of thionyl chloride and a 30-40 molar excess of N,N-dimethylformamide are employed.

Workup

  1. customThe reaction mechanism of the present invention may best be described by the following reaction scheme

Sources & evidence

ORD record
ord-4528319ddc564a6fbbcc2626b18674de
Source dataset
uspto-grants-1980_04
Patent number
US04196128

Linked notes

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