Myers modification

A novel two-step one-pot modified Woiff-Kishner reduction protocol was developed in the laboratory of A.G. Myers Myers modification). The carbonyl compound was first converted to the A/-TBS-hydrazone followed by the addition of KOf-Bu/f-BuOH in DMSO at or above room temperature. 

The Wolff-Kishner reaction is a classical reduction method of ketones to alkanes. This method involves converting the ketone to its corresponding hydrazine treatment of the resulting hydrazine with base affords the alkane and nitrogen gas. Because elevated temperatures (> 200 °C) and strong base are required, this method is harsh when sensitive functionality is present. However, milder methods have been developed including the Myers modification where the reaction temperatures are much lower (s 100 °C). 

Cyclopentenone 51 was easily prepared by treatment of halosulfone 50 with sodium acetate, a weak base.37 On the other hand, masked cyclopentenone 53 was synthesized from sulfone 52 using the Myers modification.19... 

Hart assembled olefin 109 convergently from benzyl bromide 106 by taking advantage of the Ramberg-Backlund reaction.59 As depicted below, the Sn2 displacement of benzyl bromide 106 with thiol 107 led to sulfide 108. Oxidation of 108 to the sulfone, followed by the Myers modification delivered alkene 109, an intermediate for the synthesis of C-aryl glycosides related to chrysomycins. 

Trost left the key operation at the end of his route to (+)-solamin, a natural product with a range of activities such as cytotoxicity, antimalarial and immunosuppressant activities. Applying the Myers modification, sulfone 110 was converted to butenolide diol 111 in good yield after desillylation.60... 

A quick perusal of current literature revealed that the Chan modification of the Ramberg-Backlund reaction seems to be more prevalent than the Myers modification in the latest publications. 

The thermal conductivity of pure component nonbydi ocaihon hquids may be estimated by the method of Baroncini et al., with a modification by Myers for silicon compounds, at reduced temperatures between 0.3 and 0.8 and at pressures below 3.5 MPa ... 

Myers, R.M., Fischer, S.G., Maniatis, T. and Lerman, L.S. (1985b) Modification of the melting properties of duplex DNA by attachment of a GC rich DNA sequence as determined by denaturing gradient gel electrophoresis. Nucleic Acids Research 13, 3111-3129. 

Subject to modification concerning substitution possibilities noted below, the model we have in mind is of the "putty-clay" variety. That is, although there is a choice of coefficients before a process is Installed, the coefficients are fixed thereafter. This type of model has recently been examined by Myers and Nakamura (15). Their model permits a much wider scope for choice of coefficients than the limited set actually available for producing most chemical products. 

Myers and Swiatecki (1966) have proposed a modification of the semiempirical mass equation that gives a better description of the experimental masses. This modification can be summarized in the following equation ... 

Davis MF, WangXM, Myers MD, Iwamiya JH, Kelley SS (1998) In Heinze TJ, Glasser WG (eds) Cellulose derivatives modification, characterization and nanostructures. ACS Symp Ser 688 283... 

Prosecution of this patent was in fact quite lengthy, the original application dating from August 1979, and involved questions of similarities and differences in crystalline modifications. (See Kalipharma v. Bristol-Myers 1989 for details of the history of the prosecution of the patent application.) The prior art included a 1973 patent (U.S. 

The series of litigations continued over other issues, inciuding the nature of crystal modifications (Zenith v. Bristol-Myers Squibb 1992). Zenith prepared and formulated a hemihydrate of cefadroxil, for which it submitted an ANDA to the FDA. Bristol-Myers (now Bristol-Myers Squibb) contended that the FDA should require a much more extensive new drug application (NDA) for the hemihydrate, rather than approve it within the framework of the FDA monograph for the monohydrate. BM also alleged that the Zenith product converted to the monohydrate, thereby infringing the 657 patent. Bristol-Myers theory of infringement was that the Zenith product converts to... 

This key discovery prompted further efforts to develop improved cholesterol lowering agents. For example, chemical modifications of the methylbutyryl sidechain gave simvastatin (having twice the potency of lovastatin) (Figure 10) which is also marketed by Merck. Pravastatin, marketed by Sankyo and Bristol Myers Squibb, is the 6-hydroxy open hydroxyacid derivative produced by microbial biotransformation of mevastatin (Figure 10). ... 

Davidson PW, Myers GJ, Shamlaye CF, et al Association between prenatal exposure to methylmercury and developmental outcomes in Seychellois children effect modification by social and environmental factors. Neurotoxicology 20 833-841, 1999... 

Kalapathy, U. N.S. Hettiarachchy D.J. Myers K.C. Rhee. Alkali modification of soy proteins effects of salts and disulfide bond cleavage on adhesion and viscosity. J. Am. Oil Chem. Soc. 1996, 73, 1063-1066. 

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