N-Methylephedrine → Menthol

HRID 374330

Reaction equation

COC1C=C[C:6]2N=CC=[C:9]([C@@H](O)[C@H]3N4C[C@H](C=C)[C@@H](CC4)C3)[C:7]=2[CH:8]=1.C1(C(N)CC2C=CC=CC=2)C=CC=CC=1.CC(N(C)C)C(O)C1C=CC=CC=1.[CH3:53][C:54]1([CH3:60])[CH2:56][CH:55]1[C:57](O)=[O:58]>>[CH:7]1([CH3:9])[CH2:8][CH2:56][CH:55]([CH:54]([CH3:60])[CH3:53])[CH:57]([OH:58])[CH2:6]1

Participants

Reactant 4

HCID 4374N-Methylephedrine

HCID 264821,2-Diphenylethylamine

HCID 2607082,2-Dimethylcyclopropane-1-carboxylic acid

HCID 3034034Quinine

Product 1

HCID 1254Menthol

Procedure

With 1-phenylethylamine neither a satisfactory yield nor an adequate optical purity could be achieved. Quinine yielded enantiomer in good optical purity but poor yield, no yield was indicated for N-methylephedfine With 1,2-diphenylethylamine the yield is satisfactory and the optical purity very good but the reagent, as is also N-methylephedrine is very expensive. Further, it is known that 2,2-dimethylcyclopropanecarboxylic acid can be separated into the enantiomers by the diastereomeric menthyl esters, which can be obtained from the acid chloride with (+) or (-) menthol (U.S. Pat. No. 4,487,956). This process does provide usable yields and optical purities, but is relatively complicated in working up and requires the relatively expensive menthol.

Workup

customcan be separated into the enantiomers by the diastereomeric menthyl esters, which

Sources & evidence

ORD record: ord-9ce85cc781f547289f414858807b168e
Source dataset: uspto-grants-1992_11
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US05166417

Linked notes

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