Methanesulfonic Acid → Methanesulfonic Acid

HRID 1096166Notes

Reaction equation

HRID 1096166 reaction equation
[NH:1]1[CH2:6][CH2:5][NH:4][CH2:3][C:2]1=[O:7].[F:8][C:9]([F:14])([F:13])[C:10]([OH:12])=[O:11].[CH3:15][S:16]([OH:19])(=[O:18])=[O:17].[BH4-].[Na+].C([SiH](CC)CC)C>O.O1CCCC1.O1CCOCC1.ClCCl>[NH:1]1[CH:6]=[CH:5][NH:4][CH2:3][C:2]1=[O:7].[F:8][C:9]([F:14])([F:13])[C:10]([OH:12])=[O:11].[CH3:15][S:16]([OH:19])(=[O:18])=[O:17]

Participants

12

Reactant 5

HCID 6395Methanesulfonic AcidHCID 6422Trifluoroacetic acidHCID 12052TriethylsilaneHCID 231360Piperazin-2-oneHCID 4311764Sodium borohydride

Product 3

HCID 6395Methanesulfonic AcidHCID 6422Trifluoroacetic acidHCID 19739714HCID 19739714, compound

Reagents, catalysts & solvents 4

HCID 962WaterSolventHCID 6344DichloromethaneSolventHCID 8028TetrahydrofuranSolventHCID 312751,4-DioxaneSolvent

Procedure

In step c, scheme 8, cleavage of the acetal and reductive cyclization of 29 leads to piperazinone 5A. This conversion is performed either in one step using an acid, e.g., trifluoroacetic acid or methanesulfonic acid, and a reducing agent such as sodium borohydride or triethylsilane, in solvents such as dichloromethane, 1,4-dioxane, tetrahydrofuran, water, or mixtures thereof. Alternatively, the reaction may be performed in two steps, by first forming a 3,4-dihydro-1H-pyrazin-2-one intermediate in the presence of an acid, e.g., trifluoroacetic acid or methanesulfonic acid, in a solvent such as water or dichloromethane, and subsequent catalytic hydrogenation at pressures between 1 bar and 10 bar, using a suitable catalyst, e.g., palladium on activated charcoal, in solvents such as methanol, ethanol, ethyl acetate, or mixtures thereof, at temperatures between 0° C. and 50° C.

Workup

  1. customAlternatively, the reaction

Sources & evidence

ORD record
ord-b43cda036dd74b5aac0f40200f7fcb89
Source dataset
uspto-grants-2012_03
Patent number
US08138175B2

Reaction notes

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