Methy lene

FIGURE 4 20 The bond dis sociation energies of methy lene and methyl C—H bonds in propane reveal difference in stabilities between two isomeric free radicals The secondary radical is more stable than the primary... 

Xanthatin (3-methy lene-7-methyl-6-[3-oxo-l-buten-l-y Ijcyclohep t-5-ene-[ 10,11-... 

Spiro-pyrazoline derivatives (18) are obtained smoothly from 16-methy-lene-17-ketones (17). ° The sole products formed from (18) by pyrolysis or cleavage in the presence of boron trifluoride etherate, are the 16-spiro-cyclopropyl steroids (19). ... 

Hydroxy-6-methyl-10 (5 6) abeo-cholestan-5-one acetate, 391 3 a-Hydroxy-16a-methyl-11,20-dioxo-5/3-pregnane-21-glyoxylic acid, 191 17 -Hydroxy-l-niethyl-A-homo-5a-androst-l-en-3-one acetate, 362 17 /3-Hy droxy-5a, 1 Oa-methy lene-A-norestran-3-one, 429 17 3-Hydroxy-17 a-methyl-10 ( 5 4) -fl( < o-estrane-3,5-dione, 314 3a-Hydroxy-16a-methyl-5/3-pregnane-11,20-dione, lyl... 

Asymmetric aziridination of a,P-unsaturated esters by use of N-nitrenes was studied in great detail by Atkinson and co-workers [34, 35]. Here, lead tetraacetate-mediated oxidative addition of N-aminoquinazolone 30 (Scheme 3.10) to a-methy-lene-y-butyrolactone 32 was reported to proceed with complete asymmetric indue-... 

The methylation of deoxyuridine monophosphate (dUMP) to thymidine monophosphate (TMP), catalyzed by thymidylate synthase, is essential for the synthesis of DNA. The one-carbon fragment of methy-lene-tetrahydrofolate is reduced to a methyl group with release of dihydrofolate, which is then reduced back to tetrahydrofolate by dihydrofolate reductase. Thymidylate synthase and dihydrofolate reductase are especially active in tissues with a high rate of cell division. Methotrexate, an analog of 10-methyl-tetrahydrofolate, inhibits dihydrofolate reductase and has been exploited as an anticancer drug. The dihydrofolate reductases of some bacteria and parasites differ from the human enzyme inhibitors of these enzymes can be used as antibacterial drugs, eg, trimethoprim, and anti-malarial drugs, eg, pyrimethamine. 

Homoleptic gold(III) complexes with other related dithiolate ligands, as dmit (317),1855-1864 dddt,1865,1866 l,3,5-trithiepin-6,7-dithiolate,1867 dithiosquarate (318),1868,1869 6,7-dihydro-6-methy-lene-5H-l,4-dithiepine-2,3-dithiolate,1870 3,4-thiophenedithiolate (319),1637 quinoxaline-3,3-dithiolate (320),1871 2,2-diacetylethylene-1,1-dithiolate,1872 or o-carborane-1,2-dithiolate have been... 

A carbazole-functionalized norbornene derivative, 5-CN-carbazoyl methy-lene)-2-norbornene, CbzNB, was polymerized via ROMP using the ruthenium catalyst Cl2Ru(CHPh)[P(C6Hii)3]2 [100]. The polymerization was conducted in CH2C12 at room temperature, to afford products with polydispersity indices close to 1.3. Subsequent addition of 5-[(trimethylsiloxy)methylene]-2-norbornene showed a clear shift of the SEC trace of the initial polymer, indicating that a diblock copolymer was efficiently prepared in high yield. 

Benzotriazole-related methodology publications appeared in 2006. Reaction of 1-formylbenzotriazole with triphenylphosphine/carbon tetrachloride afforded l-(2,2-dichlorovinyl)benzotriazole, where lithiation followed addition of electrophiles gave a variety of functionalized M-(ethynyl)benzotriazoles <06T3794>. Novel mono- and symmetrical di-/V-hydroxy- and IV-aminoguanidines were readily prepared from the reaction of diverse hydroxylamines or hydrazines with reagent classes di(benzotriazol-l-yl)methanimine, (bis-benzotriazol-1 -y 1-methy lene)amines, benzotriazole-1 -carboxamidines, benzotriazole-1 -... 

A. P. Rauter, J. A. Figueiredo, I. Ismael, and M. S. Pais, Synthesis of x-methy-lene-y-lactones in furanosidic systems, J. Carbohydr. Chem., 6 (1987) 259-272. 

Limited progress has been achieved in the enantioselective hydrogenation of a,/ -unsaturated carboxylic acid esters, amides, lactones, and ketones (Scheme 26.10). The Ru-BINAP system is efficient for the hydrogenation of 2-methy-lene-y-butyrolactone, and 2-methylene-cyclopentanone [98]. With a dicationic (S)-di-t-Bu-MeOBIPHEP-Ru complex under a high hydrogen pressure, 3-ethoxy pyr-rolidinone could be hydrogenated in isopropanol to give (R)-4-ethoxy-y-lactam in 98% ee [39]. 

Figure 33 shows the UPS spectra of 2,5-bis(diphenylmethy-lene)-2,5-dihydrothiophene and di-hydroselenophene, as compared with that of 2,5-bis(dithienyl methy-lene)-2,5-dihydrothiophene, together with the spectra of benezene and thiophene for references, irrespective of the central ring with sulphur or selenium the UPS spectra are found to be almost same. However, the spectra were significantly different with changing the substituent rings at the exocyclic double bonds from the phenyl to the thienyl groups. In both the phenyl and the thienyl substituents, the spectra are very similar to those of benzene and thiophene... 

Oxprenolol Tablets 20 mg Water/Methy-lene Chloride 273 74.5... 

Glycine can either be converted to serine by addition of a methy lene group from Ns,N10-methylenetetrahydrofolic acid (see Figure 20.6A), or oxidized to C02and NH4+. 

The readily available [77, 78] l,6-di-0-benzoyl-3,4-0-benzylidene-2,5-0-methy-lene-D-mannitol has been converted [79] into the benzyl ether (60), which on periodate oxidation and borohydride reduction gives the methylene acetal (61) which readily gives 1 -O-benzyl-L-glycerol for use in lipid synthesis. The acyl derivative (62) has been used [80] in glycolipid synthesis by glycosidation of the hydroxyl group. 

It is important to note that high molecular weight trans-isotactic poly(methy-lene-1,3-cyclopentane) contains no mirror or mirror glide planes of symmetry and is thus chiral by virtue of its main chain stereochemistry (it exhibits optical activity) this is in contrast to high molecular weight polypropylene and other poly(a-olefin)s, which contain an effective mirror plane perpendicular to the molecular axis in the middle of the molecule and are thus achiral [30,497],... 

C dIhC1,FNO 86483-53-6) see Ciprofloxacin ethyl o.-I (cyclopropylainino)methy lene -2,3,4,5,6-pcnta-fluoro-[i-oxobenzenepropanoate (Cid-I FjNO, 107564-01-2) see Sparlloxactn ethyl 2-[ 4-(cyclopropylcarbonyl)phenyIJ-2-methyl-propionate... 

Ci,H 7N103S 160596-25-8) see Rosiglitazonc [[ (3-methyl-2-py ridiny Damino methy lene Ipropane-dinitrilc... 

The other factor that may determine the type of cell death is the chemical structure of inducing agents [14]. We have recently found that u,(>-unsaluraled ketones such as 4,4-dimethyl-2-cyclopenten-l-one, a-methy-lene-y-butyrolactone, 5,6-dihydro-2H-pyran-2-one [15], codeinone [16], and morphinone [17] and a-hydroxylketones such as 3,3,3-trifluoro-2-hydroxy-1-phenyl-1-propanone induced caspase-independent cell death [18], induced vacuolization or autophagosome formation engulfing organelles, but without induction of apoptosis markers. 

Reaction of AT-methy lene-ftrr-bu tvl.i in i n c with octafluoroisobutylene in diethyl ether in the presence of water leads to unexpected l,3,7-oxadiazocan-4-one ring system 155 as a result of the complex sequence of reactions (Scheme 39 <1996ZOB344>). It is believed to include steps of imine hydration, cyclization accompanied by elimination of tert-butylamine, and final hydrolysis of difluoromethyl moiety into carbonyl group. 

METHYLENATION Alkyldimesitylboranes. x-Chlorobis(cyclopentadienyl)(dimethyl-aluminum)-p,-methy lene-titanium. Methylene bromide-Zinc-Titanium(IV) chloride. Organomolybdenum reagents. Titanocene methylene-Zn halide complex. N,N,P-Tri-methyl-P-phenylphosphinothioic amide. Trimethylstannylmethyllithium. 

Hsiao et al. (1992) patented a preparation of bis-methy-lene ether-linked bispyridiniiun compoimds (Figure 66.11). Bis(methanesulfonoxymethyl)ether was used to form a linker between pyridine rings, and methanesulfonate anions were replaced by chloride anions. 

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