Phosgene → 4-Isocyano-5,6-dihydro-1-benzothiophen-7(4H)-one

HRID 1730985Notes

Reaction equation

HRID 1730985 reaction equation
[N-]=C=O.[CH:4]([NH:6][CH:7]1[C:15]2[CH:14]=[CH:13][S:12][C:11]=2[C:10](=[O:16])[CH2:9][CH2:8]1)=O.C(Cl)(Cl)=O.C(N(CC)CC)C>C(Cl)Cl>[O:16]=[C:10]1[C:11]2[S:12][CH:13]=[CH:14][C:15]=2[CH:7]([N+:6]#[C-:4])[CH2:8][CH2:9]1

Participants

6

Reactant 4

HCID 6371PhosgeneHCID 8471TriethylamineHCID 105034IsocyanateHCID 23347790N-(7-Oxo-4,5,6,7-tetrahydro-1-benzothiophen-4-yl)formamide

Product 1

HCID 214946344-Isocyano-5,6-dihydro-1-benzothiophen-7(4H)-one

Reagents, catalysts & solvents 1

HCID 6344DichloromethaneSolvent

Procedure

Alternatively, formula (Ia) isocyanate can be prepared by reacting the N-formyl-4,5,6,7-tetrahydro-7-oxobenzo-[b]thiophen-4-amine of formula (IIIa) with phosgene in the presence of a tertiary amine, e.g. triethylamine, in an inert solvent such methylene chloride and other chlorinated hydrocarbons at a temperature between about 0° and 50° C and preferably between 15° and 30° C to obtain 4,5,6,7-tetrahydro-7-oxobenzo[b]thien-4-yl isocyanide of formula (IV), which is then oxidized with dimethylsulfoxide (DMSO) in the presence of anhydrous p-toluenesulfonic acid (pTSA) at a temperature between about 25° and 75° C, and preferably 25° and 50° C. The above-described reaction sequence may be graphically illustrated as follows: ##SPC3##

Sources & evidence

ORD record
ord-119fa39cc74d4a0194a1a20c51530fdc
Source dataset
uspto-grants-1976_11
Patent number
US03994924

Reaction notes

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