Aminocyclopropanes, synthesis

Thermolysis of pyrazolines was also used for aminocyclopropane synthesis. The corresponding starting materials were obtained from diazomethane and an alkene bearing a suitable nitrogen functional group, e.g. an amido or azido moiety. 

The aminocyclopropanes in equations 70 and 71 are formed by reductive pro-cesses . Electrolysis of 307 (X = Cl) gave 308 in 10 % yield this represents a less common type of aminocyclopropane synthesis by a 1,3-ring-closure. For a reductive formation of diaminobarbaralanes see Ref. 405a. 

Further applications of an azido or an isocyano function as a masked amino moiety in aminocyclopropane synthesis are described in Section II.C.3 (equation 62 and Sections II.B.l.c and II.B.2.a (Scheme 3 and equation 50). 

The reactions of dichlorocarbene with morpholine and piperidine enamines derived from cyclopentanone and cyclohexanone have been reported to lead to ring expanded and a-chloromethylene ketone products (355,356). Similarly a-chloro-a, -unsaturated aldehydes were obtained from aldehyde derived enamines (357). Synthesis of aminocyclopropanes (353,359) could be realized by the addition of diphenyldiazomethane (360) and the methylene iodide-zinc reagent to enamines (367). 

Tomato Monsanto/1994 1 -Aminocyclopropane- l-carboxyUc acid deaminase (ACCD) Pseudomonas chloraphis Delayed softening due to reduced ethylene synthesis... 

This version of the Curtius rearrangement has been applied to the synthesis of amino acid analogs and structures containing amino acids. Several m-2-aminocyclopropane carboxylate esters were prepared by selective hydrolysis of cyclopropane-1,2-dicarboxylates, followed by reaction with DPPA.267... 

Hot water treatment was reported to delay carotenoid synthesis and thus yellowing of broccoli florets (at 40°C for 60 min) and kale (at 45°C for 30 min), but did not affect Brussels sprouts (Wang 2000). Hot air treatment (38°C and 95% RH for 24 hr) slightly decreased lycopene and (3-carotene content in tomato fruit (Yahia and others 2007) however, fruit heated at 34°C for 24 hr and stored 20°C developed higher lycopene and (3-carotene than nonheated fruit (Soto-Zamora and others 2005). Moist (100% RH) hot air (48.5 or 50°C) for 4 hr caused injury to papaya and losses in lycopene and (3-carotene, but similar treatment with dry air (50% RH), alone or in combination with thiabendazole, had no effect on lycopene and (3-carotene (Perez-Carrillo and Yahia 2004). High-temperature treatment also suppressed 1-aminocyclopropane-l-carboxylic acid oxidase activity and thus indirectly prevented carotenoid synthesis (Suzuki and others 2005). 

A similar lactone ring opening is involved in the asymmetric synthesis of stereospecifically monodeuterated 1-aminocyclopropane-l-carboxylic... 

Subsequently, the asymmetric synthesis of stereospecifically monodeu-terated 1-aminocyclopropane-l-carboxylic acids (IS, 2R) and (IS, 2S) has also been achieved by a modification of the above route (89JOC270). The essential step involves an intramolecular alkylation on a lactim ether anion (Scheme 64). 

Fig. 1. Ethylene biosynthesis. The numbered enzymes are (1) methionine adenosyltransferase, (2) ACC (l-aminocyclopropane-l-carboxylic acid) synthase, (3) ethylene forming enzyme (EFE), (4) 5 -methylthio-adenosine nucleosidase, (5) 5 -methylthioribose kinase. Regulation of the synthesis of ACC synthase and EFE are important steps in the control of ethylene production. ACC synthase requires pyridoxal phosphate and is inhibited by aminoethoxy vinyl glycine EFE requires 02 and is inhibited under anaerobic conditions. Synthesis of both ACC synthase and EFE is stimulated during ripening, senescence, abscission, following mechanical wounding, and treatment with auxins.

The following review covers especially the synthesis of aminocyclopropanes it deals with compounds in which a NR R moiety (R R heteroatom) is directly bonded to the three-membered ring. Cyclopropanes with other nitrogen functional groups are not included. Literature was considered until the end of 1984 the text was supplemented in October 1985. A very short review on aminocyclopropane chemistry appeared in 1974 by Gibson and DePuy Wasserman and coworkers surveyed some aminocyclopropane compounds derived from cyclopropanones. ... 

The isocyanates (9) were transformed into amino derivatives by standard reactions. Acid-sensitive aminocyclopropanes were obtained preferentially from benzyr ) -naphthyl or trifluorethyl-urethanes which were cleaved by hydrogen, EtSNa/DMF or alkaline hydrolysis. The hydrazinolysis of phthalimido compounds obtained from the urethane and phthalic anhydride also was useful Trimethylsilylethanol proved to be advantageous for the isocyanate-amine conversion the resulting urethanes gave amines upon addition of Bu4N p- 161 (e.g. synthesis of amine (21) from truns-crysanthemic acid via isocyanate (20) S equation 3). Contrarily to... 

Koch and coworkers reported an efficient synthesis of alkoxy aminocyclopropane derivatives by the photolysis of alkoxypyrrolinones (320) . The primarily formed isocyanates (321/322) were converted into urea or urethane derivatives (323/324) (equation 76). Pyrrolinone photoreaction was shown to be a very convenient basis for the... 

Aminocyclopropanes bearing a suitable leaving group in the a-position have been extensively used for the synthesis of further aminocyclopropane derivatives. Thereby, an amino, a hydroxy, a methoxy or a trimethylsilyloxy moiety in 375 could be displaced by other substituents leading to 377. Acidic medium or a large excess of the nucleophile (as in solvolysis reactions) or activation of the leaving group (e.g. by quaternization of an amino... 

TABLE 2. Synthesis of aminocyclopropanes from other aminocyclopropane derivatives... 

J.K. Cha et al. developed a stereocontrolled synthesis of bicyclo[5.3.0]decan-3-ones from readily available acyclic substrates. Acyclic olefin-tethered amides were first subjected to the intramolecular Kulinkovich reaction to prepare bicyclic aminocyclopropanes. This was followed by a tandem ring-expansion-cyclization sequence triggered by aerobic oxidation. The reactive intermediates in this tandem process were aminium radicals (radical cations). The p-anisidine group was chosen to lower the amine oxidation potential. This substituent was crucial for the generation of the aminium radical (if Ar = phenyl, the ring aerobic oxidation is not feasible). 

Table 2. Stereoselective Synthesis of Aminocyclopropanes by the Curtins Rearrangement of Cyclopropanecarboxylic Acids...

Table 4. Synthesis of Aminocyclopropane Lactams by the Beckmann Rearrangement of Cyclopropyl Ketone Oximes...

Deamination of aminocyclopropanes and notably A-cyclopropyl-A-nitrosoureas is the mildest method known for inducing cyclopropyl to allyl rearrangement. However, the synthesis of these cyclopropyl derivatives is considerably longer than that of respective halocyclopropanes. 

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