The Preparation and Identification of Alkylcyclopropanes: 1,1,2-Trimethylcyclopropane and 1,2-Dimethyl-3-ethylcyclopropane

Abstract

as that described was heated three-quarters of an hour and then poured into 200 ml. of water.Sodium bicarbonate was added to excess.After reaction ceased, the solution was extracted twice with chloroform and the combined, dried extracts were concentrated under reduced pressure to a residual oil which was dissolved without delay in about 70-100 ml. of water and assayed spectrophotometrically. Under the conditions described, 30% was a typical yield. Addition of a few crystals of hydroquinone is advisable. Solutions without antioxidant deposit anemonin in various degrees of purity quite rapidly. The mixed m. p. of a purified sample with anemonin from natural protanemonin was not depressed.Variations in the amount of sulfuric acid used affected the rate at which the maximum yield of protoanemonin was reached, but not the yield itself. The conversion of acetylacrylic acid to protoanemonin was also achieved in solvents other than acetic acid, such as dioxane (peroxide-free), and with other catalysts, such as ^-toluene sulfonic acid.3-Bromopentene-2-olide-l,4 (VII).-The attempted dehydrobromination of the bromoacetoxy lactone (VI) with anhydrous sodium acetate in dry ether3 gave a neutral fraction which, even after fifteen hours of reflux, contained a very high bromine content.Fractionation gave material b. p. 60-64°(1 mm.) which crystallized in a Dry Ice-alcohol-bath. Rapid filtration left a colorless solid, m.p. 49-53°, which, after recrystallization from ethyl acetate, reached a constant m. p. 51-53°.

Infrared spectra of compounds containing a cyclopropane ring

“…We found that the bands observed by Allen and collaborators 27 about 3080cm-1 in the spectra .of nitrocyc1opropanes must necessarily be assigned to the 2v(N0 2 ).ss vibration 48 . In this connection we want to point out the results of the study carried out by Cole 33 who found a single band (about 3040cm -1) in the spectra of a series of natural compounds containing a three membered ring built in the molecule in a way evident from formula I. 1 II III v(CH) 3058, 3003 cm-1 v(CH) 3030, 2960 cm- 1 We measured the spectra of several compounds of this type (Table VI Nos [50][51][52][53][54] and observed that even in these compounds we may find two absorption bands of variable positions belonging to the mentioned stretching vibrations of the CH2 group. The band due to the symmetric vibration was shifted below the limit of 3000 em -1.…”

“…The CH Bond Stretching Vibration Region of I-Phenyl-I-methylcyc1opropane(1) and Phenylcyclopropane(2) …”

Synthesis and physical properties of several aliphatic and alicyclic hydrocarbons

“…This reactor was jacketed and 1 Present address, F rankl Photogra phic Services, Washington, D. C. , Prescnt address, National Institn tes of Health , Bethesda, Md . 3 Figurcs in brackets indicate the literature refereuces a t the end of this paper.…”

“…This cycloj)araffin was prepared by the reaction of zinc with 1,3-dibr0mobutane, according to the method of Bartleson, Burk, and Lankelma [3]. Several runs were made ; a typical preparation is described below.…”

“…Therefore, the emphasis was up:m highly branched paraffin hydro carbons [8] . 3 With the advent of reaction engi'les, the researches wer e directed to the syntheses of alicyclic hydrocarb )ns and the less highly branch ed aliphatics with various degrees of unsaturation. The work on the acetylenic hydro carbons is described in a previl)us paper [12] .…”