Synthesis of the Promising Chiral Synthon Isopropyl-4R-Methyl-6-Iodohexanoate from L-(-)-Menthol

Low-temperature reduction of acyclic (–)-mentholactone derivatives with diisobutylaluminum hydride in methylene chloride

“…These data allowed us to presume that the reduction of 4 involves initial formation of two diastereoisomeric organoaluminum derivatives [5] 6S-7 and 6R-7 at a ratio of 1.4 : 1.0, which was confirmed by their trans-…”

Synthesis of Optically Pure Macroheterocycle with Ester and Hydrazide Fragments on the Basis of l-Menthol

“…[2] Reesterification of cyclic ether 1 with methanol in presence of H 2 SO 4 gave methyl-(3R,6S)-6-hydroxy-3,7-dimethyl octanoate (2), [2+1]-condensation of which with absolute glutaric acid chloranhydride resulted in bis[(1S,4R)-1-isopropyl-6-methoxy-4-methyl-6-oxyhexyl]pentane dioate (4).…”

“…NMR spectra were recorded in CDCl 3 with TMS internal standard and in МеОН+С 6 D 6 with DSS internal standard on a Bruker AM-300 spectrometer (operating frequency 300. [2] (10.0 g, 58.8 mmol) in 100 ml abs. methanol three drops of conc.…”

“…Yield: 10.3 g (87%) by ester 3, the IR and NMR spectral parameters were similar to those obtained previously. [2] 1,2-Bis((3R,6S)-6-hydroxy-3,7-dimethyl-1-oxooctyl)-hydrazine, 3. To 3.00 g (14.9 mmol) of methyl-(3R,6S)-6-hydroxy-3,7-dimethyloctanoate (2) in 5 ml of dioxane 0.37 g (7.4 mmol) hydrazine monohydrate was slowly dropwise added, stirred for 4 hrs (until disappearance of 2, with TLC control); dioxane was sublimed, and the residue was filtered through Schott filter, under rinsing with 20 ml MTBE.…”