Silatrane derivative

This may be confirmed by the fact that silatrane derivatives of synthetic auxins resistant to lAA-oxidase are practically as active as auxins themselves (Table 29). 

By extensive studies of the influence of a large number of silatrane derivatives of different structure on cultures of plant tissues several very active compounds were recognized and examined in their effects on seeds, seedlings of plants and various cultivary such as tomatoes, cucumbers, grapes, flax, etc. 

The possibilities considered of application of some silatrane derivatives as specific stimulators of the growth of plants suggest that these compounds influence, in some direct or indirect way, the components of the nucleic structures (such as nucleic acids, histones) constituting the genetic apparatus of the cell. 

We have synthesized previously unknown silocyne, silocane, and silatrane derivatives of acrylic acids according to Scheme la in the presence of polymerization inhibitors. Acrylates are also obtained by concurrent synthesis on the basis of previously described halomethylsilocanes via Scheme lb. 

The silatrane derivative Ph2P(=S)OSi(OCH2CH2)3N shows N->Si to be 206 pm, silatrane 4-carboxylic acids prepared using L-N,N-bis(2-hydroxyethyl)-serine or -threonine with N- Si... 

The physical properties of commercial alkoxysilanes are provided in Table 1. Two classes of silane esters have very distinct properties and are generally considered apart from alkoxysilanes. Sdatranes are compounds derived from trialkanolamines and have siHcon—nitrogen coordination. These are generally hydrolytically stable and have unique physiological properties (3). A second special class of monomeric esters are cycHc diesters of polyethyleneoxide glycols designated sila-crowns, which have appHcation as catalysts (4). Neither silatranes nor sila-crowns are considered herein. 

Mowery and DeShong reported on the use of siloxanes 72 (Figure 16) as versatile transmetallation agents for Pd(dba)3-catalyzed couplings with aryl halides and allylic alcohol derivates, in the presence of TBAF and at high temperature (95 They later used aryl silatrane 73 (Figure 16) as a suitable partner for the fluoride-promoted... 

The most prominent biological feature of silatranes is the remarkable mammalian toxicity exhibited by their 1-aryl derivatives (Table 4). Some of them are several times more toxic than widely known poisons such as hydrocyanic acid and strychnine. At the same time 1-arylsilatranes are almost harmless for cold-blooded animals, plants, and microorganisms. For example, frogs are very resistant to 1-phenylsilatrane (9) doses of 30-40 mg/kg have no effect. 

Nitrogen-containing 1-alkylsilatrane derivatives (9, 23, 24 and 25) have low toxicity (LDS0 = 1300 - 3000 mg/kg). However, quaternization of the nitrogen atom in 1-aminoalkylsilatranes (32, 33) leads to a sharp increase in toxicity (LD50 is 540 and 240 mg/kg, respectively). l-(3 -Aminopropyl)silatrane (36) is even more toxic (LDS0 = 190 mg/kg). 

Skin-muscle wounds of 250 mm2 size were treated with an ointment consisting of the appropriate silatrane in the vaseline-lanolin base. Inflammatory signs disappeared after treatment with silatranes, especially with 1-chloromethyl- and 1-ethoxy-derivatives. By the 8—10th day of treatment the wound has almost completely been epithelialized, but for a small spot in the centre covered with crust... 

Table 19. Antitumorous activity of carbofunctional derivatives of silatrane XSi[(OCH2CH2)2/(C>CHRCH2)lN and homosilatrane XS i (OCH 2CH2CH2)/(OCHRCH 2) 2)N...

These studies were followed by investigation of antitumorous activity of car-bofunctional derivatives of silatrane and homosilatrane79,80. The results obtained are listed in Table 19. The criterion of efficacy was life span of the test animals as compared to the untreated ones. The observations lasted 60 days. 

To explain the great interest in silatranes in recent decades one should bear in mind two points. First, for a long time silatranes remained the only accessible class of neutral derivatives of pentacoordinated silicon. Second, the specific physiological action of many silatranes refuted the traditional opinion that organosilicon compounds do not differ much... 

Use of triethanolamine derivatives allows various substituents to be introduced into the silatrane ring, as illustrated in equations 5-752-58. 

These results enabled one to employ the solution-phase 15N NMR chemical shifts for estimating of the length of the Sk— N bond in solute silatrane patterns28,263,266,2711. This approach made use of equation 53, which was derived from the corresponding solid-state and gas-phase data263 ... 

Silatranes 20 and 20a are readily converted to a,/1-epoxy derivatives 89 and 89a (83-96% yield) by treatment with m-chloroperbenzoic acid in dichloromethane at room temperature (equation 125)141,350. Only polymeric products are obtained from 1-allylsilatrane (76) under the same conditions350. 

Aminopropyl)silatranes (105 and 105a) react with halogen-containing compounds including acyl chlorides (equations 140 and 141)96 99 365 366 and with aldehydes (equation 142)366 367 to give the corresponding derivatives (106-108). 

The reactivity diminishes in going from thiomethyl to thioethyl derivatives. Thus, 1-(phenylthiomethyl)silatrane is oxidized by 80% H202 to the corresponding sulfoxide whereas l-(phenylthioethyl)silatrane is unreactive even under more drastic conditions. 

Treatment of l-(mercaptoalkyl)silatranes with organomercury acetate in chloroform affords the corresponding mercury derivatives in 80-85% yield (equation 148). A related reaction with diorganylmercury results in lower product yields372. 

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