9α-Fluoro-11-deoxy Steroids¹

Abstract

SCPFLUORO-~ DEOX OXY STEROIDS 2633 and the methylene dichloride layer of the filtrate was dried over Acknowledgment.-Appreciation is extended to fifrs, sodium sulfate. This solution was concentrated to a residual G. A. Snyder for technical assistance, to M~. H~~~~~ solid which was heated for 1 hr. with 50 ml. of acetic anhydride and 100 ml. of pyridine. Cooling of the reaction mixture and Warrington for gas chromatographic analyses, to Dr. dilution with 3 1. of cold water gave a solid which was recrystal-B. F. Tullar and Mr. E. J. Johnson for checking and lized once from ethyl acetate. The 176-acetoxy-5a-androstan-3-refining the procedure for preparation of the 2-one so obtained (62 g., 497, yield) melted a t 156-159'. Its identity was confirmed by infrared spectral comparison with an ketone under Optimum and to Dr. c. F. authentic sample.Koelsch for helpful discussions.

4.05 Addition of HX Reagents to Alkenes, Alkynes, and Allenes without Transition Metal

“…The use of less volatile solutions of HF with an organic base 1 such as acetone was first used by Bergstrom in the fluorination of double bonds in steroids. 2 Olah et al later established that HF-30% (w/w) pyridine was a convenient reagent for the hydrofluorination of alkenes as well as other fluorination reactions. 3 Yoneda developed HF-melamine as less hygroscopic and superior to other HF-base solutions not only with regard to hydrofluorination activity for alkenes but also in relation to its preparation and ease of handling.…”

“…The best regioselectivity were observed with the carbamate containing a 2,2,2-trichloroethoxycarbonyl (Troc)submotif (equation 7). 14 DG R R = alkyl, aryl DG = NHCO 2 R′, CO 2 …”

“…87 This method can also be applied to cyclohexene and cyclopentene to give 1-acetamidocylohexane and 1-acetamidocyclopentane, respectively, in good yields (equation 124 Ritter reaction has been applied in the total synthesis of natural products. 88 For example, the enantioselective biomimetic total synthesis of the alkaloid (+)-aristotelone was accomplished by Heathcock et al 88b The synthetic sequence commenced with a Hg (NO 3 ) 2 Organic azides are versatile intermediates for organic synthesis. The hydroazidation of C-C multiple bonds is one of the efficient methods for synthesis of organic azides.…”

Composition and structure of heteroassociates formed in the HF-N, N-dimethylformamide binary liquid system

“…As a re sult, the intensity of the bands of the smaller associate in the subtracted spectrum is substantially higher than that in the spec trum from which the former spectrum is subtracted, and the absorption minima are observed in the ΔA/S spectrum instead of the maxima of these bands. ing one DMF molecule and two systems containing two DMF molecules each) are 1 : 1 HA (3)(4)(5). Seven associ ates (five associates with one DMF molecule each (6)(7)(8)(9)(10) and two associates with two DMF molecules each (11 and 12)) are characterized by the 4 : 1 stoichiometric ratio of the molecules.…”

Development and applications of novel HF-based fluorination reagents : DMPU-HF.

“…34 Few years later, Olah and co-workers explored the synthetic utility of Pyridine/HF mixture and came up with interesting findings of its applicability. No wonder the reagent is being regarded today as Olah's reagent or pyridinium poly(hydrogenfluoride) (PPHF).…”