1 -Azido-3- propan

One of the most efficient methods for the generation of 2,5-dideoxy-2,5-iminogalactitol 16 relies on the fuculose-1-phosphate aldolase-catalyzed aldol condensation of 2-azido-3-hydroxypropanal with dihydroxyacetone monophosphate (Scheme 13.17). The same method, applied to (2/ )-2-azidopropanal R)-V7 and to (25 )-2-azido-propanal (5 )-17, allows for the preparation of 2,5,6-trideoxy-2,5-imino-D-allitol 18 and 2,5,6-trideoxy-2,5-imino-L-talitol 19, respectively [22]. 

In another procedure, 2-aminobenzophenone is acylated with an sc-azido acid in the presence of l-[3-(dimethylamino)propyl]-3-ethylcarbodiimide and the product 23 is converted into a benzodiazepinone by reductive cyclization with propane-1,3-dithiol (Method F).200... 

Lithium aluminum hydride reduced )J-azidoethylbenzene to j8-aminoethyl-benzene in 89% yield [600], The azido group was also reduced with aluminum amalgam (yields 71-86%) [149], with titanium trichloride (yields 54-83%) [601], with vanadous chloride (yields 70-95%) [217] Procedure 40, p. 215), with hydrogen sulfide (yield 90%) [247], with sodium hydrosulfite (yield 90%) [259], with hydrogen bromide in acetic acid (yields 84-97%) [232], and with 1,3-propanedithiol (yields 84-100%) [602]. Unsaturated azides were reduced to unsaturated amines with aluminum amalgam [149] and with 1,3-propane-dithiol [602]. 

Lithium-2-propan-nitronat reagiert mit 4-(l-Azido-l-methyl-ethyl)-l-nitro-benzol in Ge-genwart von Phosphorsaure-bis-[dimethylamid] zu 4-Nitro-l-(2-nitro-l,1,2-trimethyl-pro-pyl)-benzol (92 %)2 l0. 

Propane 2-(3-Azido-hexafluoro-propyloxy)-he.xafluoro-1-(tri-fluoro-ethenyloxv)- E15/2. 1612 (—CO,/NaF)... 

Butanol 3-Azido- Vl/la, 1, 420f. Propan 1-Azido-l-methoxy- E14a/2. 

Propan 2-Azido-2-(2-hydroxy-4-methyl-cyclohexyl)- EI6a, 1247 (En + HNj)... 

Propan l-Azido-1-ethoxy-2-phenyl-E14a/2, 291 (0-Si-enol/HN3/ R-OH)... 

Thus, addition of iodine monochloride and sodium azide to 1 -methylcyclobutene in acetonitrile gave rra i-l-azido-2-iodo-l-methylcyclobutane (1) in 70% yield. Lithium aluminum hydride reduction of this trans-0L,p- odiethyl ether at 20 °C gave, instead of the expected l-methyl-5-azabicyclo[2.1.0]pentane, the product of ring contraction, i.e. 1-aminoethylcyclo-propane (3). Formation of an intermediate 2-iodocyclobutylamine, which then underwent C4 -> C3 ring contraction, analogously to the 2-halocyclobutanols (Section 4.1.2.2.1) appeared likely to explain this result. 

The pyrrolidines were also prepared by using chemoenzymatic strategy for constructing the required azido-sugars (Scheme 1) Enzymatic aldol condensation of 2-azido-3-hydroxy propanal (35) and DHAP gave a diastereoisomeric mixture of 30 and 31, which... 

Conventional base-catalyzed alkylation of thioindoxyl 1,1-dioxide with unreactive alkyl halides does not proceed cleanly the products 66 (X = H, Y = alkyl) are better obtained by alkylation in the presence of the sterically hindered base, diisopropylethylamine, in propan-2-ol.287 Thioindoxyl 1,1-dioxide reacts as expected in the Michael reaction e.g., with acrylonitrile, 66 (X = H, Y = CH2CH2CN) is obtained. Treatment of thioindoxyl 1,1-dioxide with p-toluenesulfonyl azide288 or 2-azido-3-ethylbenzothiazolium tetrafluoroborate289 affords the diazo compound 66 (XY = N2), which gives the 2-methoxy compound 66 (X = H, Y = OMe) when treated with MeOH-Cu-HC104.288... 

A later-developed method to obtain amines from azides consists in their reduction with propane-1,3-dithiol,employing ethyldiisopropylamine as a base. The transformations reported proceeded rapidly and resulted in, 2-trans selectivity. Unverzagt described the reduction of the azido heptasaccharide 221 by this dithiol method, to give exclusively the p amine 222. In contrast, reduction of 221 by Raney nickel resulted in both anomers 222 and 223, with p a = 7 3. A corresponding reduction of the azido octasaccharide gave a 52% yield however, a low yield of 35% was observed in the reduction of the thio sugar azide 68 with propane-1,3-dithiol... 

An extensive study revealed that the A-dithiasuccinyl-protected azide 224 offers a major advantage in the synthesis of A-glycans. Efficient reduction of the A -dithiasuccinyl- and azido-functionality in 224 could be achieved, either in solution by utilizing simultaneous in situ reduction with Zn in THE AcOH AC2O, or on solid phase upon treatment with ethyldiisopropylamine and an excess of dithiothreitol, propane-1,3-dithiol, or 2-mercapto-A-methylacetamide leading to the known 1 or 225. 

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