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Quenching procedures for reactions to prepare triflate compounds with primary or secondary amines

IP.com Disclosure Number: IPCOM000233230D
Publication Date: 2013-Dec-03
Document File: 1 page(s) / 43K

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Quenching procedures for reactions to prepare triflate compounds with primary or secondary amines

Disclosed hereinafter is a general procedure to prepare triflate compounds.

For example, a procedure to prepare vinyl triflate compounds which involves the interaction of enolizable ketones with triflic anhydride in the presence of a base according to the scheme below.

OTf

Usually to quench reactions for preparing triflate compounds H2O or aqueous mixtures of inorganic bases (Na2CO3; NaHCO3) are added. In order to destroy residual triflic anhydride also organic primary or secondary amines can be used with analogous results in terms of yield and quality.

Example 1:

A mixture of compound A and a base (Py, TEA, NaHCO3, Na2CO3) in dichloromethane (DCM) was cooled to - 10°C, then triflic anhydride was added. The reaction mixture was stirred at -10°C for 5-10 h and then quenched with a primary or secondary amine selected from diisopropylamine, n-dipropylamine, isopropylamine, n-propylamine. The mixture was then diluted with H2O and, after the phase separation, the organic phase was concentrated to residue to give compound B as a crude material.

Example 2:

Hydroxyandrost-5-en-17-one-3-acetate was dissolved in DCM (10-20 Vol) and Na2CO3 was added. The resulting mixture was cooled to below 0°C, and then triflic anhydride (1.0-2.0 eq.) was added over 5 min. The reaction mixture was kept under stirring below 0°C for 5-7 hours, and then it was heated to 5°C and quenched wi...