Pentanal, 5-amino

In the absence of base, the trimer can rearrange to iso-tripiperidein, a product of self-condensation.10,17 Tn the presence of base, however, a-tripiperidein is stable for over a year. In solution, tripiperidein readily detrimcnzes to the monomer, which is in equilibrium with S-amino-valeraldehyde [Pentanal, 5-amino-].8... 

Pentanal, 5-amino [14049-15-1], 121 Pentane, 1-bromo- [110-53-2], 82 Pentanediotc acid [ 110-94-1 ], 98 3-Pentenoicacid, 4-methyl- [504-85-8], 70 3-Penten-2-ol, 3-bromo-, acetate [14362-79-9], 35... 

Amino-pentan 5-Amino-nonan 2-Amino-1,3-diphenyl-propan... 

Dimethylamino-l-(2-dimethyl-amino-ethenyl)- V/2c, 641 Pentan 5-Amino-l-benzylamino-E16d. 898 (NH-OH - NH2) Phthalazin 2,3-Diethyl-l,2,3,4-tetrahydro- El6a, 572 (alkylier. Red.)... 

A solution of 25.8 g. (0.20 mole) of 4-amino-2,2,4-trimethyl-pentane (ierf-octylamine) (Note 1) in 500 ml. of C.P. acetone is placed in a 1-1. three-necked flask equipped with a Tru-Bore stirrer and a thermometer and is diluted with a solution of 30 g. of magnesium sulfate (Note 2) in 125 ml. of water. Potassium permanganate (190 g., 1.20 moles) is added to the well-stirred reaction mixture in small portions over a period of about 30 minutes (Note 3). During the addition the temperature of the mixture is maintained at 25-30° (Note 4), and the mixture is stirred for an additional 48 hours at this same temperature (Note 5). The reaction mixture is stirred under water-aspirator vacuum at an internal temperature of about 30° until most of the acetone is removed (Note 6). The resulting viscous mixture is steam-distilled approximately 500 ml. of water and a pale-blue organic layer are collected. The distillate is extracted with pentane, the extract is dried over anhydrous sodium sulfate, and the pentane is removed by distillation at atmospheric pressure. The residue is distilled through a column (Note 7) at reduced pressure to give 22-26 g. (69-82%) of colorless 4-nitro-2,2,4-trimethylpentane, b.p. 53-5473 mm., < 1.4314, m.p. 23.5-23.7°. 

The Rh2(DOSP)4 catalysts (6b) of Davies have proven to be remarkably effective for highly enantioselective cydopropanation reactions of aryl- and vinyl-diazoacetates [2]. The discovery that enantiocontrol could be enhanced when reactions were performed in pentane [35] added advantages that could be attributed to the solvent-directed orientation of chiral attachments of the ligand carboxylates [59]. In addition to the synthesis of (+)-sertraline (1) [6], the uses of this methodology have been extended to the construction of cyclopropane amino acids (Eq. 3) [35], the synthesis of tricyclic systems such as 22 (Eq. 4) [60], and, as an example of tandem cyclopropanation-Cope rearrangement, an efficient asymmetric synthesis of epi-tremulane 23 (Eq. 5) [61]. 

E. l-Amino-2-phenylaziridine (Note 23). If the pentane solution from Step D is removed on a rotary evaporator at room temperature, 7.5-7.7 g. (82-85%) of l-amino-2-phenylaziridine, suitable for preparative use, is obtained. Kugelrohr distillation of this material on a 1-2 g. scale (0.01 mm./60-65° oven temperature) (Note 24) gives a recovery of over 90% (Notes 23 and 25). 

CgHgNO 99-92-3) see Acetohexamide l-amino-5-(A-acetylhydroxyamino)pentane (C7H1JN2O2 144108-69-0) see Deferoxamine... 

Fig. 2.34 The two conformations free of destabilizing syn-pentane interaction [215, 216] in 2,4-disubstituted y-amino acid derivatives with like and unlike configuration. According to the nomenclature proposed by Balaram...

Out of the two conformations of the like-y -am no acid backbone (Fig. 2.34) that do not suffer from syu-pentane interaction, conformation II is almost identical to that found into the 2.6-hehcal structure reported for y" -peptides. This suggest that avoidance of unfavorable sy -pentane interactions in y-amino acids substituted at both the 2 and 4 positions can be used as an additional element of de-... 

Optimal pre-organization of the y-peptide backbone towards the formation of open-chain turn-like motifs is promoted by unlike-y " -amino acid residues. This design principle can be rationalized by examination of the two conformers free of syn-pentane interaction (f and II", Fig. 2.34). Tetrapeptide 150 built from homo-chiral unlike-y -amino acid building blocks 128e has been shown by NMR experiments in pyridine to adopt a reverse turn-like structure stabilized by a 14-mem-bered H-bond pseudocycle [202] (Fig. 2.37 A). 

The proline-catalyzed reaction has been extend to the reaction of propanal, butanal, and pentanal with a number of aromatic aldehydes and proceeds with high syn selectivity.197 The reaction can also be carried out under conditions in which the imine is formed in situ. Under these conditions, the conjugative stabilization of the aryl imines leads to the preference for the aryl imine to act as the electrophile. A good yield of the expected P-aminoalcohol was obtained with propanal serving as both the nucleophilic and the electrophilic component. The product was isolated as a 7-amino alcohol after reduction with NaBH4. 

Ion pairing between the amino group of baclofen and pentane sulfonic acid is primarily responsible for the chromatographic behavior of baclofen on a reversed-phase octadecylsilane column. However, the transformation... 

Several other non-nitrogenous products have been identified as products of the Maillard reaction. These include butanol, butanone, butane-dione, and pentane-2,3-dione as well as dihydroxyacetone, glycer-aldehyde, and D-erythrose. Obviously, the same products are present after mild acidic or basic degradation of carbohydrates. Thus, the necessity of an amine or amino acid in the mechanism of their formation is uncertain. 

Since the more highly strained bicyclopropylidene (1) and methylenespiro-pentane (6), both spirocyclopropanated analogs of methylenecyclopropane (2), are even more reactive than the latter, it is to be expected that analogs of the amino acids 287 and 288 containing a bicyclopropylidenyl or a methylenespiro-pentyl moiety would also exhibit biological activities. In fact, the preparations of the amino acids 289 and 290 as well as of the methylenespiropentane amino acid 295 have been reported in the meantime (Scheme 65) [55]. 

The stereoinductive effect of the a-substituent is often more powerful when this substituent is a polar group such as an alkoxy or amino gronp. In this instance as well, minimization of syn-pentane interactions with 3-monosnbstituted reagents is important, and the selectivity can be amplified if it acts in concert with other effects. Known models inclnde the stereoelectronic preference... 

The Knovenagel condensation under basic conditions was first investigated with D-glucosamine chlorhydrate (28.HC1) as the sugar. The condensation of this reducing amino sugar with pentane-2,4-dione 1 in aqueous acetone in the presence of sodium carbonate afforded the pyrrole derivative 29 in 85% yield [99] (Scheme 5). The reaction was extended to other 2-amino-2-deoxy-aldose and carbon nucleophiles [100-104]. 

Combes synthesis with pentan-2,4-dione that led to 157, was ascribed to unfavorable steric hindrance in the alternative orientation in the Combes synthesis. 2-Amino-l,4-dimethylcarbazole underwent the Skraup reaction in the only orientation available to it. Finally, the carbazol-1-yIhydrazone of ethyl pyruvate underwent normal Fischer indolization giving 158 its 3-isomer gave an indole by cyclization at C-4 producing 159. ... 

A solution of 1 equiv of (S)- or (/ )-2-methoxymetliyl-1-[(2,2-dimethyl-l,3-dioxan-5-ylidene)amino]pyrro-lidine in THF (4 mL/mmol) is cooled to — 78 °C. 1.1 Equiv of tert-butyllithium in hexane (1.7 M) are added dropwise and the mixture is stirred for 2 h at — 78 °C. The solution of the metalated hydrazone is cooled to — 100 CC, 1.2 equiv of the alkyl halide (neat or as a solution in anhyd THF) are added dropwise, and the mixture is stirred for 1 h at —100 °C and then warmed slowly to r.t. (about 15 h). Finally, diethyl ether (30 mL/mmol) is added and the mixture is washed with pH 7 buffer (3 mL/mmol) and two 3-mL portions of brine, dried over MgSO and evaporated under reduced pressure. The Crude product is heated to 50 C for a short time if necessary (about 15 min for isomerization from the Z- to the L-isotiler monitored by TLC) and purified by silica gel column chromatography (diethyl ether/ pentane, 1 1 -2 5 Rf - > RfZ-iso-mer) to give a colorless or pale yellow product. See Table 2 for physical data. 

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