N-Pentyl chloride

Figure 2 Four representative Grignard reagents plotted according to Eq. (5) cyclohexyl bromide vs. cyclopentyl bromide ( ) cyclopentyl chloride vs. cyclopentyl bromide (A) n-pentyl chloride vs. cyclohexyl chloride ( ) neopentyl bromide vs. cyclopentyl bromide (O)- (From Ref. 81b.)...

The need for a targeted method arose because of the n-butyl chloride reactant used in the synthesis of LY297802. This starting material contains as impurities the n-propyl and n-pentyl chloride homologs as well as the isobutyl isomer. Since these impurities will react to form the corresponding impurities in the drug substance (SMI-3), the quality of the n-butyl chloride... 

The yield of ethyl n -pentyl ether formed from the reduction of 1-pentanal by Et3SiH/TFA in ethanol is 57% after 6-8 hours at 50-60°.327 The yield of product increases to 72% when one equivalent of ethyl orthoformate and some anhydrous hydrogen chloride are added to the reaction medium.327 Presumably, this reduces the amount of free water in the reaction medium. 

Di-w -pentyl Ether [TMSI-Catalyzed Reduction of an Aldehyde to a Symmetrical Ether].314 A mixture of sodium iodide (0.15 g, 1 mmol), 1-pentanal (1.06 mL, 10 mmol), and trimethylsilyl chloride (2.0 mL, 15.4 mmol) was stirred in MeCN (5.0 mL) at room temperature for 10 minutes, after which 1,1,3,3-tetramethyldisiloxane (TMDO, 1.79 mL, 10 mmol) was added. When the exothermic reaction had ended (30 minutes), a solution of 2.5 N HF in MeOH (30 mL) was added to the reaction mixture, which was then refluxed for 5 minutes. Work-up was carried out by diluting the solution with CH2CI2 (40 mL), washing with water (30 mL) and saturated aqueous NaHC03 solution (20 mL), drying, and evaporating the solvents. Crude di-n-pentyl ether was purified by distillation 0.65 g (84%) bp 185-1897760 Torr. 

Chemical Name n-amyl chloride, 1-chloropentane, pentyl chloride... 

A mixture of 153 mg (0.85 mmol) of olivetol, 132 mg (0.87 mmol) of (-i-)-cjs//rans-p-mentha-2,8-dien-l-ol and 200 mg of anhydrous magnesium sulfate in 5 mL of methylene chloride was stirred and cooled to ice bath temperature. Fifty microliters of anhydrous stannic chloride (0.111 g, 0.4 mmol) was added and stirring and cooling was continued. After 10 minutes, the reaction mixture was analyzed by gas-liquid chromatography and shown to contain 30 percent of (-)-6a,10a- rans-l-hydroxy-3-n-pentyl-6,6,9-trimethyl-6a,7,8,10a-tetrahydrodibenzo[b,d]pyran. After quenching the reaction with sodium carbonate, the desired compound can be isolated from the reaction mixture. 

Isomerization is observed with higher alkyl halides, as in Friedel-Crafts reactions isopropylphosphonic dichloride is stated to be the sole product from n-propyl chloride,190,191 and terf-pentyl chloride undergoes C-C fission, yielding the tert-butyl acid.193 On reduction by lithium tetrahydroaluminate the phosphonic chloride formed from w-butyl chloride gives a primary phosphine that is shown by 31P-nuclear magnetic resonance to consist of n- and sec-butylphosphine in the proportions 5 95 and the product from n-octyl chloride was similarly shown to contain all four position isomers.194... 

Rather surprisingly, if the hydroxy group is replaced by a halogen atom, elimination of HX (X = Cl or Br) appears to prefer a five-membered transition state (Equation 2.53). Deuterium-labeling studies with n-butyl and -pentyl chloride demonstrate that abstraction of the hydrogen from the y-carbon is the favored process. There are also indications that cyclic chlorides and bromides eliminate HX by the 1,3-mechanism. 

Pol y ( (1 -amidoe thylene ) -co- (1 -N-(1,1,N4,N4-Te tramethy1-4-ammonium-pentyl chloride))amidoethlene))... 

These reactions provide an interesting contrast in mechanisms. The n-butyl bromide synthesis proceeds by an Sj 2 mechanism, whereas f-pentyl chloride is prepared by an S l reaction. 

EXPERIMENT 23 Synthesis of n-Butyl Bromide and t-Pentyl Chloride 201... 

As your instructor indicates, perform either the n-butyl bromide or the f-pentyl chloride procedure or both. 

The adducts of either butyllithium with DPE (1,1-diphenylhexyllithium) or polymeric organolithiums with DPE are the preferred initiators for polymerization of a wide variety of alkyl methacrylates and (ert-butyl acrylate [3]. For example, Stiihn and coworkers [77] recently reported the synthesis of well-defined, narrow molecular weight distribution polymers from methyl, ethyl, n-propyl, -butyl, n-pentyl, and n-hexyl methacrylates using the adduct of scc-butyllithium and DPE as initiator in THF at -78 °C in the presence of lithium chloride. This initiator was also used recently to copolymerize 2-tri-methylsiloxyethyl methacrylate and butyl methacrylate using analogous reaction procedures [78]. 

If further acidic C—H bonds in the molecule cause problems, the tin-trick can be applied. The asymmetric deprotonation of a bifunctional carbamate (39a) is accomplished at an early stage and the masked carbanionic centre carried through the synthesis as a stan-nyl group. For instance, the (S)-5-silyloxy-l-tributylstannyl-pentyl carbamate 39b (> 95% ee) was produced by the usual means and converted by standard steps via the aldehyde 78 into the allyl chloride 79 (equation 17) . Lithiodestannylation of 79 by n-BuLi proceeds faster than reductive lithiation in the allylic position to form the lithiocarbamate 80,... 

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