One step process for regioselective synthesis of α-acyloxy carbonyls

Patent metadata

Field	Value
Publication number	US-9834570-B2
Application number	US-201414895442-A
Country	US
Kind code	B2
Filing date	Jun 3, 2014
Priority date	Jun 3, 2013
Publication date	Dec 5, 2017
Grant date	Dec 5, 2017

Abstract

A regioselective N-Heterocyclic Carbene (NHC) catalyzed one step process for high yield synthesis of α-acyloxy carbonyl compounds is disclosed.

First claim

The invention claimed is:

1. A single-step, one pot process for the preparation of an α-acyloxy carbonyl compound of general formula (I);

wherein R is selected from H, alkyl, aryl, Bn; R 1 is selected from H, alkyl, substituted aryl, unsubstituted aryl, —CH 2 OTBS (TBS=Tertiary butyl silyl), —CH 2 OBn, —OR, OMOM (Methoxy methelene); Ar is selected from unsubstituted/substituted phenyl group or pyridine group; R and R 1 optionally can combine to form a ring structure containing 3 to 6 carbon atoms and may optionally contain a heteroatom;
comprising the steps of: reacting alkene of formula (II) with an aldehyde of formula (III)

in the presence of a N-Heterocyclic carbene catalyst (NHC) selected from

wherein for IVb, Ar=2,4,6-(CH 3 ) 3 C 6 H 2 ; for IVc, Ar=2,6-iPr 2 C 6 H 3 , a halogen source, tri-ethyl amine and a solvent in oxygen atmosphere at a temperature in the range of 15-30° C. by stirring for a period in the range of 10-50 hours to obtain a compound of general formula (I); wherein R is selected from H, alkyl, aryl, Bn; R 1 is selected from H, alkyl, substituted aryl, unsubstituted aryl —CH 2 OTBS (TBS=Tertiary butyl silyl), —CH 2 OBn, —OR, OMOM (Methoxy methelene); Ar is selected from unsubstituted/substituted phenyl group or pyridine group.

2. The process as claimed in claim 1 , wherein N-Heterocyclic carbene catalyst is Iva[-IVf, preferably Iva.]

3. The process as claimed in claim 1 , wherein halogen source is selected from the group consisting of N-bromo succinamide (NBS), N-iodo succinamide NIS or N-chloro succinamide NCS.

4. The process as claimed in claim 1 , wherein solvent used is di-methyl sulfoxide (DMSO).

5. The process as claimed in claim 1 , wherein the N-Heterocyclic carbene catalyst is IVa and the yield of the compound of general formula (I) is in the range of 70 to 92%.

6. The process according to claim 1 , wherein representative compound of general formula (I) are:
2-Oxo-2-phenylethyl 4-nitrobenzoate (1a);
2-(4-Methylphenyl)-2-oxoethyl 4-nitrobenzoate (1b);
2-(4-Bromophenyl)-2-oxoethyl 4-nitrobenzoate (Ic);
2-(4-Fluorophenyl)-2-oxoethyl 4-nitrobenzoate (Id);
2-(4-Acetoxyphenyl)-2-oxoethyl 4-nitrobenzoate (Ie);
2-(3,4 Dimethoxyphenyl)-2-oxoethyl 4-nitrobenzoate (If);
1-Oxo-2,3-dihydro-1H-inden-2-yl 4-nitrobenzoate (Ig);
2-Oxo-1,2-diphenylethyl 4-nitrobenzoate (Ih);
1-Oxo-1-phenylpropan-2-yl 4-nitrobenzoate (Ii);
2-((Tert-butyldimethylsilyl)oxy)-1-oxo-1-phenylpropan-2-yl 4-nitro benzoate (Ij);
3-(Benzyloxy)-2-oxopropyl 4-nitrobenzoate (Ik);
3-Oxooctyl 4-nitrobenzoate (II);
2-Oxodecyl 4-nitrobenzoate (Im);
2-Oxo-4-phenylbutyl 4-nitrobenzoate (In);
2-Ethoxy-2-oxoethyl 4-nitrobenzoate (Io);
2-Oxotetrahydro-2H-pyran-3-yl 4-nitrobenzoate (Ip);
2-(Methoxy)-2-oxo-1-phenylethyl 4-nitrobenzoate (Iq);
2-Oxo-2-phenylethyl benzoate (Ir);
2-Oxo-2-phenylethyl 3-methylbenzoate (Is);
2-Oxo-2-phenylethyl 4-bromobenzoate (It);
2-Oxo-2-phenylethyl 4-chIorobenzoate (Iu);
2-Oxo-2-phenylethyl nicotinate (Iv).

7. The process as claimed in claim 1 , wherein halogen source is N-bromo succinamide (NBS).

Assignees

• Council Scient Ind Res

Inventors

• Sudalai Arumugam
• Reddi Rambabu
• Malekar Pushpa

Classifications

• C07D307/60

  Two oxygen atoms, e.g. succinic anhydride · CPC title

• C07C205/57

  having nitro groups and carboxyl groups bound to carbon atoms of six-membered aromatic rings of the carbon skeleton · CPC title

• C07D213/803

  Processes of preparation · CPC title

• C07D309/30

  Oxygen atoms, e.g. delta-lactones · CPC title

• C07C67/39 Primary

  by oxidation of groups which are precursors for the acid moiety of the ester · CPC title