Reducing agents Group

Group V hydrides are reducing agents, the reducing power increasing from NH3 to BiHa, as thermal stability decreases. 

Some of the functional groups which are reduced by lithium aluminium hydride, the reduction product together with the theoretical mols of reducing agent required (in parenthesis) are listed below —... 

Table 1. Reaciivicy of reducing agents towards functional groups (adapted from J. B. Hendrickson, O. J. Cram, and G. S. Hammond, Organic Chemistry, 3rd ed., McGraw-Hill 1970, with modi(icaiiotis. ...

Formic acid is a good reducing agent in the presence of Pd on carbon as a catalyst. Aromatic nitro compounds are reduced to aniline with formic acid[100]. Selective reduction of one nitro group in 2,4-dinitrotoluene (112) with triethylammonium formate is possible[101]. o-Nitroacetophenone (113) is first reduced to o-aminoacetophenone, then to o-ethylaniline when an excess of formate is used[102]. Ammonium and potassium formate are also used for the reduction of aliphatic and aromatic nitro compounds. Pd on carbon is a good catalyst[103,104]. NaBH4 is also used for the Pd-catalyzed reduction of nitro compounds 105]. However, the ,/)-unsaturated nitroalkene 114 is partially reduced to the oxime 115 with ammonium formate[106]... 

Reduction of arenes by catalytic hydrogenation was described m Section 114 A dif ferent method using Group I metals as reducing agents which gives 1 4 cyclohexadiene derivatives will be presented m Section 1111 Electrophilic aromatic substitution is the most important reaction type exhibited by benzene and its derivatives and constitutes the entire subject matter of Chapter 12... 

The reaction of an alkyl halide with lithium is an oxidation-reduction reac tion Group I metals are powerful reducing agents... 

Much of the chemistry of diols—compounds that bear two hydroxyl groups—is analo gous to that of alcohols Diols may be prepared for example from compounds that con tain two carbonyl groups using the same reducing agents employed m the preparation of alcohols The following example shows the conversion of a dialdehyde to a diol by... 

Ammonia reacts with the ketone carbonyl group to give an mine (C=NH) which is then reduced to the amine function of the a ammo acid Both mine formation and reduc tion are enzyme catalyzed The reduced form of nicotinamide adenine diphosphonu cleotide (NADPH) is a coenzyme and acts as a reducing agent The step m which the mine is reduced is the one m which the chirality center is introduced and gives only L glutamic acid... 

The /-butyldimethylsilyl group introduced by TBDMIM has a number of advantages in protecting alcohols (6). The sdylated alcohol hydroly2es more slowly than an alcohol sdylated with TMS by a factor of 10 . The sdyl ether is also stable to powerful oxidi2ing and reducing agents, but it can easily be removed by aqueous acetic acid or tetrabutylammonium fluoride in tetrahydrofuran. 

A group of violet titanium(III) acylates has been prepared from TiCl and alkafl carboxylates. AH of the acylates are strong reducing agents similar to TiCl (189). Studies of Ti(III) compounds include the reaction (190)... 

Reducing agents are thought to work by reduction of the chromophoric carbonyl groups in textiles or pulp. 

Certain base adducts of borane, such as triethylamine borane [1722-26-5] (C2H )2N BH, dimethyl sulfide borane [13292-87-OJ, (CH2)2S BH, and tetrahydrofuran borane [14044-65-6] C HgO BH, are more easily and safely handled than B2H and are commercially available. These compounds find wide use as reducing agents and in hydroboration reactions (57). A wide variety of borane reducing agents and hydroborating agents is available from Aldrich Chemical Co., Milwaukee, Wisconsin. Base displacement reactions can be used to convert one adduct to another. The relative stabiUties of BH adducts as a function of Group 15 and 16 donor atoms are P > N and S > O. This order has sparked controversy because the trend opposes the normal order estabUshed by BF. In the case of anionic nucleophiles, base displacement leads to ionic hydroborate adducts (eqs. 20,21). 

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