Strauss reaction

The hydroxy derivatives 29, a preparatively most valuable (see Section 2.2.2) class of functionalized cyanoacetyienes, are obtained when the propargylic alcohols 28 are first subjected to the Strauss reaction and the resulting bromoacetylenes are subsequently treated with cuprous cyanide in dimethylformamide [34, 35] [Eq. (9)]. 

The easily accessible bromoacetylenes 135 are normally obtained by the Strauss reaction, the treatment of terminal acetylenes with alkaline solutions of sodium or potasium hypo-bromite [Eq. (22)], which has turned out to be of great value in this area [79, 80). 

The additive coupling of terminal alkynes catalyzed by copper is a classical reaction known as the Strauss coupling. Unfortunately, under the... 

Data taken from article by Horman and Strauss, J. Chem. Education, 46 (114), 1969.] If reaction (A) may be considered as an irreversible reaction, what is the order of this reaction with respect to BHB The initial concentration of BHB is 360 moles/m3. The water is present in sufficient excess that its concentration may be considered to be essentially constant. What is the reaction rate constant ... 

A selective heating in liquid/liquid systems was exploited by Strauss and coworkers in a Hofmann elimination reaction using a two-phase water/chloroform system (Fig. 2.10) [32]. The temperatures of the aqueous and organic phases under micro-wave irradiation were 110 and 55 °C, respectively, due to the different dielectric properties of the solvents (Table 2.3). This temperature differential prevented decomposition of the final product. Comparable conditions would be difficult to obtain using traditional heating methods. A similar effect has been observed by Hallberg and coworkers in the preparation of /3,/3-diarylated aldehydes by hydrolysis of enol ethers in a two-phase toluene/aqueous hydrochloric acid system [33],... 

These reactions were next revisited by Strauss and it was shown that, under identical conditions in xylene, the reaction rates were strictly identical within experimental error [14]. 

In the first studies performed at Northwestern, Steven Strauss found that AlBr3 brought about a moderate increase in the rate of CO uptake by Mn(CO)5(CH3). Susan Butts then discovered that the reaction occurs in two steps. The first is a very rapid CO insertion to yield a cyclic product, equation 8a, which is followed by the much slower uptake of CO, equation 8b. 

An, J., Bagnell, L., Cablewski, T., Strauss, C.R., Trainer, R.W. 1997. Applications of high temperature aqueous media for synthetic organic reactions. J Org Chem 62 2505-2511. 

Keire, D.A., Strauss, E., Guo, W., Noszal, B., Rabenstein, D.L. Kinetics and equilibria of thiol/disulfide interchange reactions of selected biological thiols and related molecules with oxidized glutathione. J. Org. Chem. 1992, 57, 123-127. 

Melezhik, V.A., Fallick, A.E., Hanski, E.J., Kump, L.R., Lepland, A., Prave, A.R., Strauss, H. 2005. Emergence of the aerobic biosphere during the Archean-Paleoproterozoic transition Challenges of future research. GSA Today, 15, 4-11. Phillips, O.M. 1990. Flow controlled reactions in rock fabrics. Journal of Fluid Mechanics, 212, 263-278. 

In 1994, Strauss et al. [45] reported a continuous flow microwave-assisted setup to perform a range of synthetic reactions (Fig. 3). 

Cationic Group 11 carbonyl complexes have been implicated in catalytic carbony-lation reactions of alkenes, arenes, alcohols, saturated hydrocarbons and aldehydes under acidic conditions [106]. While the mono- and di-carbonyls [M(CO)] and [M(C0)2] (M = Cu, Ag, Au) can be formed at atmospheric pressure of CO, only Cu(I) forms a tricarbonyl cation under such conditions [107]. Strauss and co-workers reported the observation of [Ag(CO)3] when a Fluorolube mull of Ag[Nb(OTep5)5] was subjected to 13 bar CO in an HP IR transmission cell [108]. 

Halogenoalkynes are also formed from alkynes and aqueous solutions of hypohalites. In these reactions, alkynylide anions are transient intermediates. The conversions give good results only when the acetylene has a low pK (e.g. aryl-feCH and ROCCsCH) or good solubility in water (e.g..HC-CCXCHj OH) [122], The hypohalite method of Strauss [123] has most applications in the synthesis of bromoacetylenes. 

Other nucleophilic additions conducted in aqueous media can be found in the literature (Lubineau et al., 1994 Strauss, 1999). These reactions will include the benzoin condensation, the Prins reaction, and the Wittig-Horner reaction, and the Baeyer-Villi-ger oxidation. 

Some interesting synthetic applications have been found by Strauss for the interactions of 3,5-dinitropyridine with carbanions, as generated in situ by base-promoted CH ionization, to yield bicyclic systems by meta bridging,12 under conditions favoring a similar reaction with 1,3,5-trinitrobenzene.9 3,5-Dinitropyridine reacts with 1,3-diphenyl-2-propanone and triethylamine to give the bridged ion 76, according to Scheme 5. The reaction consists... 

Raner, K.D., Strauss, C.R., Vyskoc, F. and Mokbel, L., A comparison of reaction-kinetics observed under microwave irradiation and conventional heating, J. Org. Chem., 1993, 58, 950. 

Several workers have employed monomodal cavities for microwave chemistry on the sub-gram scale. In some cases in which monomodal cavities have been used7, special benefits of so-called focussed microwaves have been claimed. As mentioned earlier, the dielectric properties of a sample can alter substantially with temperature and/or with changing chemical composition. Hence, regardless of whether multi-modal or unimodal cavities are employed, frequent tuning may be necessary if heating efficiency is to be retained. This aspect has often been overlooked by proponents of focussed microwaves. The nett result is that transfer of microwave conditions between monomodal to multi-modal cavities is usually facile. With the MBR (which had a tunable multimodal cavity), Cablewski et al. performed five reactions that had been conducted earlier on the gram scale or below with focussed microwaves (T. Cablewski, B. Heilman, P. Pilotti, J. Thorn, and C.R. Strauss, personal communication see also Ref. 117 for conference poster). These were scaled-up between 40- and 60-fold and reaction conditions... 

Strauss, C.R. and Trainor, R.W., Reactions of ethyl indole-2-carboxylate in aqueous media at high temperature, Aust. J. Chem., 1998, 51, 703. 

Strauss, C.R., Microwave-assisted reactions in organic synthesis are there any nonthermal microwave effects Comments, Angew. Chem. Int. Ed., 2002, 41, 3589. 

Tripathi GNR (1998) Electron-transfer component in hydroxyl radical reactions observed by time resolved resonance Raman spectroscopy. J Am Chem Soc 120 4161-4166 TsaiT, Strauss R, Rosen GM (1999) Evaluation of various spin traps for the in vivo in situ detection of hydroxyl radical. J Chem Soc Perkin Trans 2 1759-1763 Tsay L-Y, Lee K-T, Liu T-Z (1998) Evidence for accelerated generation of OH radicals in experimental obstructive jaundice of rats. Free Rad Biol Med 24 732-737 Ulanski P, von Sonntag C (2000) Stability constants and decay of aqua-copper(lll) - a study by pulse radiolysis with conductometric detection. Eur J Inorg Chem 1211-1217 Veltwisch D, Janata E, Asmus K-D (1980) Primary processes in the reactions of OH radicals with sul-phoxides. J Chem Soc Perkin Trans 2 146-153... 

Roberts and Strauss, 2005). As was described earlier, an added advantage to microwave chemistry is that often no solvent is required. In recent years, many commercial reactors have come on the market and some are amenable for scaling up reactions to the 10 kg scale. These new instruments allow direct control of reaction conditions, including temperature, pressure, stirring rate and microwave power, and therefore, more reproducible results can be obtained. For most successful microwave-assisted reactions, a polar solvent that is able to absorb the energy and efficiently convert it to heat is required, however, even solvents such as dioxane that are more or less microwave transparent can be used if a substrate, coreagent or catalyst absorbs microwaves well. In fact, ionic liquids have been exploited in this field as polar additives for low-absorbing reaction mixtures. 

Almost three decades ago, Strauss and co-workers 18) carried out classic work on polysoaps (23) comprised of poly-4-vinylpyridine which had been quatemized on up to 38 % of the nitrogens with n-dodecyl bromide those nitrogens that escaped reaction with n-dodecyl bromide were then derivatized with ethyl bromide. Now addition of KBr to an aqueous solution of a polyelectrolyte normally decreases the viscosity. This is not true for the 38 % polysoap (23) where the viscosity increases with... 

Cordes and co-workers 191 found that the alkaline hydrolysis of p-nitrophenyl hexanoate is subject to catalysis by polyvinylpyridine-based polysoaps. For example, k bs is increased from 0.1 mm to 1.4 mm in the presence of 5 x 10 7 M 38% polysoap (23) (the same material used in the Strauss work). With 5 x 10-7 M polymer having a 15 % dodecyl content, the rate is increased only 3 times above background. The simplest rationale for the kinetics invokes both hydrophobic and electrostatic forces. Thus, dodecyl chains on the polymer hydrophobically bind p-nitrophenyl hexanoate to the polymer surface. Since the polymer possesses a high density of cationic nitrogens, hydroxide ions also accumulate at the polymer surface where they catalyze the hydrolysis of bound ester. Addition of nitrate ion to the aqueous reaction... 

The specific features of meta-cyclization of aza-aromatic compounds with bifunctional nucleophilic reagents were formulated by Strauss in a number of papers on the reactions of polynitro aromatics and their aza-analogues with enamines, CH-active acetamidines, and other 1,3-dinucleophiles (74ACR181). 

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