Facilities methods for

The treatment of ketoximes with lithium aluminum hydride is usually a facile method for the conversion of ketones into primary amines, although in certain cases secondary amine side products are also obtained. Application of this reaction to steroidal ketoximes, by using lithium aluminum deuteride and anhydrous ether as solvent, leads to epimeric mixtures of monodeuterated primary amines the ratio of the epimers depends on the position of the oxime function. An illustrative example is the preparation of the 3(x-dj- and 3j5-di-aminoandrostane epimers (113 and 114, R = H) in isotopic purities equal to that of the reagent. 

A facile method for the stereospecific labeling of carbon atoms adjacent to an oxygenated position is the reductive opening of oxides. The stereospecificity of this reaction is due to virtually exclusive diaxial opening of steroidal oxides when treated with lithium aluminum hydride or deuteride. The resulting /ra/w-diaxial labeled alcohols are of high stereochemical and isotopic purity, with the latter property depending almost solely on the quality of the metal deuteride used. (For the preparation of m-labeled alcohols, see section V-D.)... 

Schneider, B., and Budzikiewicz, H. A facile method for the localization of a double bond in aliphatic compounds. Rapid Commun. Mass Spectrom.. 4. 550, 1990. 

This procedure provides a facile method for converting substituted 1-methyl-3,4-dihydroisoquinolines into the corresponding 2-(2-acet-... 

This facile method for removing organotin impurities was developed by... 

A facile method for the oxidation of alcohols to carbonyl compounds has been reported by Varma et al. using montmorillonite K 10 clay-supported iron(III) nitrate (clayfen) under solvent-free conditions [100], This MW-expedited reaction presumably proceeds via the intermediacy of nitrosonium ions. Interestingly, no carboxylic acids are formed in the oxidation of primary alcohols. The simple solvent-free experimental procedure involves mixing of neat substrates with clayfen and a brief exposure of the reaction mixture to irradiation in a MW oven for 15-60 s. This rapid, ma-nipulatively simple, inexpensive and selective procedure avoids the use of excess solvents and toxic oxidants (Scheme 6.30) [100]. Solid state use of clayfen has afforded higher yields and the amounts used are half of that used by Laszlo et al. [17,19]. 

Recently, reaction of a propargylic alcohol with diethyl chlorophos-phite in the presence of a tertiary amine has been found to be a facile method for the direct preparation of allenicphosphonates (Equation 4.37).167... 

Iwasawa and co-workers developed a facile method for the construction of polycyclic indole derivatives 190a and 190b by the tungsten(0)-catalyzed reaction of A-(2-(l-alkynyl)phenyl)imine 188 with the electron-rich alkenes 189a and 189b (Scheme 32).42b Photoirradiation of a mixture of imine 188 and ketene silyl acetal 189a with 10mol% of... 

These procedures illustrate facile methods for the preparation of benzenediazonium-2-carboxylate and its derivatives14 and of biphenylene and certain biphcnylene derivatives.13 The latter preparation is far more convenient and proceeds in much better yield than do previous syntheses, which involve more steps, less accessible intermediates, and more complicated techniques. 

Hodosi and Kovac reported the highly efficient P-mannosylation, which makes use of mannose-derived 1,2-O-stannylene acetal 15 in combination with an aglycon-derived triflate (Scheme 7.13).58 A remarkable feature of this method is its extreme simplicity. Even totally unprotected mannose can be used as precursor of 15. Undoubtedly, this method can be seen as one of the most facile methods for the stereoselective synthesis of P-mannosides. 

Ballenweg, S. Gleiter, R. Kratschmer, W. Chemistry at Cyclopentene Add ds on [60]Fullerene. Matrix-Assisted Laser De-sorption-Ionization-TOF-MS (MALDI-TOF MS) As a Quick and Facile Method for the Characterization of Fullerene Derivatives. Synth. Met. 1996, 77, 209-212. 

A facile method for the synthesis of N-substituted 2-benzimidazolinones 142 has been developed by Romero et al. (96TL2361) using A-substituted ureas 139, which are cyclized to 142 with IBTA as an oxidant. The reaction probably proceeds via intermediates 140 and 141. Besides the iV-alkyl or aryl substituent, presence of the 1-methoxy group is necessary for the success of this cyclization. Another benzimidazoles synthesis involves cycli-zation of N-phenyl-C-alkyl formimidamides with IBD [95JCS(P1)615]... 

Because of the polyfunctional nature of carbohydrates, protective-group strategy plays an important role in synthetic methodology involving this class of compounds. In the present Chapter, results are described from a study of the utility of N-trimethylsilyl- and N-tert-butyldimethylsilyl-phthalimide for the selective silylation of primary hydroxyl groups in carbohydrates. Also described, is a new, facile method for cleavage of acetals and dithioacetals in carbohydrate derivatives the method involves treatment of the derivatives with a dilute solution of iodine in methanol. 

This procedure illustrates a highly selective and facile method for introducing a phenylsulfonyl group into the Z-position of 1,3-diene systems by using commercially available starting materials. The method can be applied to cyclic as well as acyclic systems giving 2-(pheny1sulfonyl)-l,3-dienes. In an alternative synthesis via condensation of allyl sulfone with aldehyde and subsequent acylation-elimination, the 2-(phenylsulfonyl)-l,3-dienes obtained are limited to acyclic systems. 

A facile method for the oxidation of nucleoside H-phosphonates to phosphates has been developed with BTSP and N,0-bis(trhnethylsilyl)acetamide, MeC(NSiMe3)OSiMe3, in the presence of Me3Si0S02CF3 as a catalyst (equations 67 and 68) °. 

In a similar manner, intramolecular cyclization of the O-stannyl ketyl derivatives 201 and 206, generated from the oxazolyl aldehydes 200 and 205, provides a facile method for the chiral synthesis of 3-hydroxy-2-(hydroxymethyl)-5-substimted-pyrrolidines 202 and 203 and the piperidine analogues 207 and 208 that can be successfully transformed into naturally occurring amino alcohols, (+)-bulgecinine 204 and (—)-desoxoprosopinine 209, respectively (Fig. 

The attention focused on facile methods for obtaining heterocycles of this type has led to recent utilization of some of them as intermediates in synthesis, inasmuch as certain ones, such as muscarine,24 have been obtained from natural sources, and various others have been shown to have interesting biological properties.25... 

Fluorodcsulfurizations of thiols,311 phenyl thioglycosides,290 1,2-dithiolans.312 aromatic dithiocarboxylic acids,399 or orthothioesters313 in hydrogen fluoride systems with N-chloro-or N-bromosuccinimide as a coagcnt are facile methods for the generation of monofluorides, gem-difluorides, and trifluoromethyl derivatives, e.g. formation of 11,311 12,312 13,313 and... 

Benzenesulfonyl chloride in pyridine remains a powerful and facile method for the efficient synthesis of optically pure depsipeptides. Nevertheless, various new approaches based upon the mixed anhydride methodology have been introduced into depsipeptide chemistry. 

Hydroxo bridge cleavage in the presence of anionic nucleophiles, which is a facile method for the synthesis of mixed bridge complexes,... 

A facile method for the preparation of a variety of stabilized arsonium ylides in good yield has been developed by the action of active methylene compounds with tertiary arsine oxide or tertiary arsine dihalide. Thus triphenyl-arsine dihalides react with a number of active methylene compounds in the presence of a tertiary amine to afford arsonium ylides (6) (40). The reaction of triphenylarsine oxide with active methylene compounds in the presence of either acetic anhydride or triethylamine-phos-phorus pentoxide gave rise to arsonium ylides (6) (32, 36. 65, 67). 

Carbozincation of alkenes is a very facile method for the formation of new C—C bonds. A smooth intramolecular reaction occurs when functionalized 5-hexenyl iodides are treated with diethylzinc in ether, followed by acid work-up (equation 106)416. 

As already mentioned at the beginning of this chapter, one of the facile methods for the synthesis of dihydropyrimidine derivatives is the treatment of oc,(3-unsaturated carbonyls with urea and its analogues—thiourea, guanidine and amidines. However, the majority of the publications have dealt with syntheses involving thiourea. Most likely is the possibility of the modification of 3,4-dihydropyrimidine-2-thiones or their heteroaromatized analogues, which produces a diverse class of heterocycles. The reagent involved in this modification process can act like a,(3-unsaturated carbonyls [16] (Scheme 3.9). 

W. M. Macindoe, A. H. van Oijen, and G. -J. Boons, A unique and highly facile method for synthesizing disulfide linked neoglycoconjugates a new approach for remodelling of peptides and proteins, Chem. Commun. (1998) 847-848. 

J. S. Myers and O. Gabriel, Specific conversion of D-galacturonic acid residues in glycoproteins a facile method for carbohydrate linkage-analysis, Carbohydr. Res., 67 (1978) 223-234. 

Finally, the thermal and high-pressure mediated IRDARs of an oximino-malonate dienophile 94 tethered to a dienic carboxylic acid offer a facile method for regioselective synthesis of substituted pyridines 96 after aroma-tization of the adducts 95 with CS2CO3 (Scheme 28) [68]. 

One of the most facile methods for construction of the (i-lactam skeleton would be [2 + 2] cyclo additions of isocyanates to alkenes. However, the [2 + 2] cycloadditions of alkyl or aryl isocyanides with either 2,3-dihydrofuran or vinyl ethers often fails under normal conditions. High pressure can surmount this difficulty in certain cases. For instance, alkyl isocyanates 125 underwent [2 + 2] cycloadditions with such cyclic vinyl ethers as 126 to produce the P-lactams 127 (Scheme 34) [80]. 

Jensen et al. [125] investigated an HPLC/ICP-MS with sulfur-specific detection, as a method for obtaining metabolite profiles for omeprazole administered as 1 1 mixture of 32S- and 34S-labeled material. Analysis based on the monitoring of the chromatographic eluent at either m/z 32 or m/z 34 was not successful due to insufficient sensitivity caused by interferences from polyatomic ions. However, reaction of sulfur with oxygen in the hexapole collision cell, combined with monitoring at m/z 48 (for 32S) or m/z 50 (for 34S), provided a facile method for metabolite profiling. Detection at m/z 48 was superior in sensitivity to detection of m/z 50. 

You, J. Chen, S. Chen, Y. A facile method for the synthesis of 6-alkylation products of l,3-dialkyl-5-fluorouracil. Synth. Commun. 2001, 33, 1541-1545. 

Hara, O. Ito, M. Hamada, Y. Novel N-C acyl migration reaction of acyclic imides a facile method for a-amino ketones and / -amino alcohols. Tetrahedron Lett. 1998, 39, 5537—... 

Dayal B, Ertel NH ProteinChip technology a new and facile method for the identification and measurement of high-den-sity lipoproteins apoA-I and apoA-II and their glycosylated products in patients with diabetes and cardiovascular disease. 

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