Reductive conditions

Entry Indole substituents Reduction conditions Yield (%) Ref... 

Batch syntheses comparable to those used for MDA produce 3,3 -dimethy1methy1enedi(cyclohexylamine) marketed under the trade name Laromia C-260. The starting aromatic diamiae, 3,3 -dimethy1methy1enediani1ine [838-88-0] is prepared from o-toluidine [95-53-4] condensation with formaldehyde. Similarly 3,3 -dimethyldicyclohexylaniiae [24066-10-2] may be produced (38) from o-toHdine [119-93-7] derived from o-nitrotoluene [88-72-2]. The resultant isomer mixtures are dependent on reduction conditions as ia MDA hydrogeaatioa. 

Ring expansion of ftve-membered ring heterocycHc compounds has been accompHshed to form pyridine derivatives. Reaction of tetrahydrofurfuryl alcohol with ammonia gives pyridine (1) under dehydrogenating conditions, and gives piperidine (18) under reductive conditions. 

Arylalkylsulfones ate important intermediates obtained by alkylation of arylsulfinic acids. The latter ate obtained by reduction of the corresponding sulfonyl chloride. This reduction process is simple and of general appHcation involving the addition of the isolated sulfonyl chloride paste to excess aqueous sodium sulfite followed by salting-out the product and isolation. With mote rigorous reduction conditions, such as zinc/acid, sulfonyl chlorides ate reduced through to aryknercaptans, eg, 2-mercaptonaphthalene is manufactured from naphthalene-2-sulfonyl chloride. 

When reductive conditions are contraindicated, the indirect removal of chlorine by oxidation of a derived hydrazino derivative with silver oxide, may be used this is illustrated... 

The A-ring of the 17-ol (25) derived from equilenin 3-methyl ether is reduced rapidly under Birch reduction conditions, since the 1,4-positions are unsubstituted. The B-ring is reduced at a much slower rate, as is characteristic of aromatic compounds in which 1,4-reduction can occur only if a proton enters an alkylated position. Treatment of (25) with sodium and t-butyl alcohol in ammonia reduces only the A-ring to afford the corresponding 1,4-dihydro compound in over 85% yield.On the other hand,... 

This reaction does not need any special handling and the reduction conditions commonly used witli lithium aluminum hydride (see chapter 2) are equally applicable with lithium aluminum deuteride. 

In a related study, the precursor 41 could be amiulated either by irradiation or by treatment with palladium acetate in acetic acid to provide indolocarbazoles 42 and 43 in yields of 37% and 55%, respectively (Scheme 8). Both products were eventually deprotected efficiently to give 44 and transformed further under reductive conditions to staurosporinone 45, the aglycone of 8, Alternatively, a shorter route encompassing deprotection of 41, followed by cychzation by irradiation in the presence of iodine and subsequent reduction, gave 45 in an even better overall yield (98T6909). 

Dimethyl l-methyl-1 7f-l-benzazepine-3,4-dicarboxylate (1) is reported to be resistant to catalytic reduction (conditions not specified), whereas with sodium amalgam in methanol, and with zinc and hydrochloric acid, the 4,5-dihydro- 2 and 2,3-dihydro- 3 compound, respectively, is formed.12... 

The placement of the NOx bed ahead of the oxidation bed causes a delay of the warm-up of the oxidation bed from a cold start. Since many of the materials considered for the reduction of NO are also excellent oxidation catalysts, the NOx bed is often used as the oxidation bed by the injection of secondary air during the first two minutes from a cold start. After the oxidation bed is warmed up, the secondary air is diverted from upstream of the first bed to upstream of the second bed. This procedure helps the emission reduction when the catalysts are fresh, but hastens the aging of the NOx catalyst as it is being exposed repeatedly to oxidation and reduction conditions. 

Compound oso angle (deg.) CSC angle (deg.) C—S length (pm) Reduction conditions and yield of sulphide... 

Ordinary alkenes are usually unaffected by Birch-reduction conditions, and double bonds may be present in the molecule if they are not conjugated with the ring. However, phenylated alkenes, internal alkynes (p. 1009), and conjugated alkenes (with C=C or C=0) are reduced under these conditions. 

Our group has also reported that the alkylation products of 4-cyano-l,3-diox-anes can serve as substrates for radical atom transfer reactions [41]. One such example is shown below (Eq. 17). Slow addition of tributyltin hydride/AIBN to a refluxing solution of cyanohydrin 115 generated the radical nitrile transfer product 116. This method, though somewhat limited in scope, can provide access to syn-l,3-diols which maybe unstable to the vigorous Li/NHg reduction conditions. 

CuCl, especially in a single crystal form, is extensively used as an optical material for its special optical properties. Orel et al. [2] first proposed a new method to obtain CuCl particles by the reduction of Cu with ascorbic acid. Several dispersants were used in the reduction and monodispersed CuCl particles can be obtained by selecting the proper dispersant and reduction conditions. In this work, the above method was used to modify the traditional process of CuCl preparation, namely, by reducing the Cu " with sodium sulfite to obtain the highly active CuCl catalyst to be used in the direct process of methylchlorosilane synthesis. 

Suhtnicion nickel powders luive been synthesized successfully from aqueous NiCh at various tempmatuTKi and times with ethanol-water solvent by using the conventional and ultrasonic chemical reduction method. The reductive condition was prepared by flie dissolution of hydrazine hydrate into basic solution. The samples synthesized in various conditions weae claractsiz by the m ins of an X-ray diffractometry (XRD), a scanning electron microscopy (SEM), a thermo-gravimetry (TG) and an X-ray photoelectron spectroscopy (XPS). It was found that the samples obtained by the ultrasonic method were more smoothly spherical in shape, smaller in size and narrower in particle size distribution, compared to the conventional one. 

This XPS investigation of small iron Fischer-Tropsch catalysts before and after the pretreatment and exposure to synthesis gas has yielded the following information. Relatively mild reduction conditions (350 C, 2 atm, Hg) are sufficient to totally reduce surface oxide on iron to metallic iron. Upon exposure to synthesis gas, the metallic iron surface is converted to iron carbide. During this transformation, the catalytic response of the material increases and finally reaches steady state after the surface is fully carbided. The addition of a potassium promoter appears to accelerate the carbidation of the material and steady state reactivity is achieved somewhat earlier. In addition, the potassium promoter causes a build up on carbonaceous material on the surface of the catalysts which is best characterized as polymethylene. 

This Study has shown that reasonably uniform platinum crystallites can be made on y-alumlna, and that platinum and palladium can be segregated and maintained In that form for the most part even after exposure to high temperature oxidation-reduction conditions. Highly dispersed clusters of palladium, nickel, cobalt, and Iron can be observed. Cluster size determination could not be accurately made because of the lack of contrast between the cluster and the support. The marginal detectability by EDS for these clusters enabled elemental Identification to be made, however, mass uniformity determinations could not be made. 

Table 2 Reduction conditions used to obtain the parents compounds Bfz and Fz from Bfx and Fx and other reactions...

Fx Zn dust/NH4Cl (30%)/THF/reflux Fz When 3-chloromethyl-Fx derivative was submitted to these reduction conditions a fcisfurazan was generated as a reductive dimerization Zn-promoted process [38]... 

Thick sedimentary pile from middle Miocene to late Pliocene is exposed in the Oga Peninsula, northern Honshu, Japan (Fig. 1.153). Age of the sedimentary rocks has been determined by microfossil data. Thus, the sedimentary rocks in the Oga Peninsula where type localities of Miocene sedimentary rocks in northern Japan are well exposed have been studied to elucidate the paleoenvironmental change of the Japan Sea (Watanabe et al., 1994a,b). Kimura (1998) obtained geochemical features of these rocks (isotopic and chemical compositions) and found that regional tectonics (uplift of Himalayan and Tibetan region) affect paleo-oceanic environment (oxidation-reduction condition, biogenic productivity). However, in their studies, no detailed discussions on the causes for the intensity and periodicity of hydrothermal activity, and temporal relationship between hydrothermal activity, volcanism and tectonics in the Japan Sea area were discussed. They considered only the time range from ca. 14 Ma to ca. 5 Ma. 

Organic solvents or mixtures of water and solvents such as acetone or water-acetone are commonly used to extract chemicals from sediment samples as for upland soil. An analysis of sediment, collected from waterways or extremely low Eh paddies, frequently requires the removal of sulfur-containing species, although there is little interference from sulfur if the sediments are in a not very reductive condition. Reduced copper and silver nitrate columns are usually used for the removal, but these procedures are not always successful. Recovery studies could be needed to confirm an interference with sulfur. 

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