Phenyl tetrazole ether

Chloro-l-phenyl-lH-tetrazole Phenyl tetrazole ether Palladium on carbon... 

It-yel pities, mp 177-78°. It was prepd by heating phenyl-(4-nitrophenyl)-dichloromethane with Ag azide in diisoamyl ether (Refs 1 St 4) lr(4mnitropbenyl)-5 phenyl tetrazole,... 

Unsubstituted tetrazolyl derivative 458 was also prepared according to the following procedure (91MIP2). A solution of 5-phenyl-2-trityltetrazole in tetrahydrofuran was first treated with 1.7 M ferf-butyllithium in pentane at -25°C, in two parts. After about 30 minutes, an organolithium salt precipitated. Then a 1 M ethereal solution of zinc chloride was added to the mixture, which was then warmed to room temperature. Bis(triphenyl-phosphine)palladium(Il) chloride and 4//-pyrido[l,2-a]pyrimidin-4-one 457 were added to the reaction mixture, and after boiling for 4 hours, the 2-trityl derivative of 458 was obtained in 56% yield. Finally, detritylation with a mixture of methanol and concentrated hydrochloric acid yielded tetrazole derivative 458. 

After cooling the reaction mixture in an ice-bath, the inorganic salts were removed by filtration and washed with acetone. The combined filtrates were concentrated in vacuo. The residual syrup was diluted with saturated brine and extracted with three portions of diethyl ether. The gathered extracts were dried over anhydrous magnesium sulfate, clarified with charcoal and treated with ethereal hydrogen chloride until precipitation was complete. The solid was slurried in diethyl ether and decanted several times, filtered and air-dried to give 3.8 g (86%) of tan 4-(2-di-n-propylaminoethyl)-7-(l-phenyl-lH-tetrazol-5-yloxy)-2(3H)-indolone hydrochloride. Recrystallization from 200 cc of hot acetonitrile gave 2.6 g (59%) of microcrystalline product, m.p. 245°C. 

An improved method for the removal of methylenedioxy-groups in alkaloids of the benzylisoquinoline and tetrahydroberberine series has been derived. Alkaloids such as remneine (26) can be converted into the dihydroxy-bases (27) by treatment with boron trifluoride followed by 5-chloro-5-phenyl-l//-tetrazole and subsequent hydrogenolysis of the resulting bis-tetrazolyl ethers. The yields in the process are good.39... 

Recently, a new and efficient synthesis of cyprodime from naltrexone (2) has been reported [73], Firstly, the tetrazolyl ether (27) was formed by reaction of naltrexone with 5-chloro-l-phenyl-1 Ff-tetrazole [74], Catalytic hydrogenation afforded 3-deoxynaltrexone (28) which was methylated with dimethyl sulphate to give the enol ether (29). Acid hydrolysis gave the known morphinanone (30) [75] which was treated with activated zinc and ammonium chloride to yield the phenol (31). 4-O-Methylation with phenyltri-methylammonium chloride afforded cyprodime (23, Scheme 3.4) [75],... 

To a solution of Br2 (16.0 g, 0.1 mol) in glacial HOAc (250 mL) at 55 °C was added portionwise, with continuous stirring, 3-phenyl-5-(tetrazol-5-yl)formazan-l-carboximidamide (1, Ar = Ph 12.9 g, 50 mmol). The rate of addition was such as to maintain a temperature of 53-58 °C (30 min). A small amount of yellow solid remained following the completion of addition which was removed by filtration. The filtrate was poured onto ice and the resulting red solid was collected. The crude product was titurated with warm Et20, the mixture filtered and the filtrate concentrated. The residue was recrystallized (Et20/petroleum ether, bp 30-60°C) to give red plates yield 4.15 g (35%) mp 131-132"C. 

Removal of an aromatic methylenedioxy grotgf. This reaction can be carried out in three steps. Treatment with boron trichloride is known to cleave methylenedioxy groups preferentially (4, 43). The catechol group is then removed by etherification with S-chloro-l-phenyl-l-Zf-tetrazole and hydrogenolysis of the ether, An example is formulated. ... 

The tetrazole-based cycloaddition chemistry was subsequently applied to protein labeling in bacteria cells via a genetically encoded O-aUyl-tyrosine (O-allyl-Tyr, Scheme 8c) [41]. In this study, the reactions between tetrazole derivatives and aUyl phenyl ether were first investigated. The formation of nitrile imine was found to be fast (<2 min) but the cycloaddition steps was slow ( 2 = 0.00202 M s with allyl phenyl ether in 1 1 PBS/MeCN 75-fold slower than acrylamide). In-gel... 

The concept of silyl enol ether synthesis via / -elimination from a Brook rearrangement-derived carbanion also appeared in Wicha s studies on additions of 1-phenyl-l//-tetrazol-5-yl (PT) sulfonyl anions to acyl silanes. When PT sulfone 34 was deprotonated in the presence of acyl(triphenyl)silane, ketone 36 was isolated in good yield after hydrolysis of the silyl enol ether intermediate 35. The mechanism involved addition of the... 

In a further example, a genetically encoded alkene-containing protein in Escherichia coli was modified with a library of 2,5-diaryl tetrazoles under similar conditions (Song et al., 2008). Although the photoinduced formation of the nitrile-imine was very fast (2 min), the subsequent cycloaddition with the aUyl phenyl ether functional protein was considerably slower (the reaction was allowed to proceed overnight at 4 °C). By comparison, the second-order rate constant of the cycloaddition with allyl phenyl ether was determined to be 0.00202 0.00007 M s, whereas that for acrylamide (as was used in the previous example) was determined to be 0.15s. A reasonable explanation for this observation is the lower LUMO energy of acrylamide than that of allyl phenyl ether, which offers better orbital overlap with the HOMO of the nitrile imine. 

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