Short step

As the electrons move from cathode to anode, they undergo elastic and inelastic collisions with gas atoms. The paths of the electrons are not along straight lines between the electrodes because of the collisions. In effect, the movement of each electron consists of short steps between... 

Nakamura, H., et al. (2000). Convergent and short-step synthesis of dl-Cypridina luciferin and its analogues based on Pd-mediated cross coupling. Tetrahedron Lett. 41 2185-2188. 

Nonetheless, it was a fairly short step from octopus compounds to dendrimers, and the step was taken by Vogtle in the late 1970s when he attempted to use a cascade reaction to prepare a molecule of the dendrimer type that would now be considered a dendron rather than a fully developed dendrimer. It began with the addition of acrylonitrile to an anfine, followed by reduction of the nitrile to amine. This was followed by a further reaction with acrylonitrile, and the process was repeated several times to yield highly branched macromolecules. There were initially problems with the reduction step but these were overcome, and the preparation of these poly(propylene imine) dendrimers was later commercialized. 

In summary, it seems but a short step from the conclusions of Lou-rengo or of Kraut, reached at the virtual beginning of structural organic chemistry, to the consideration of much longer chain molecules and to the realization that such products necessarily would consist of mixtures of molecular species difficult to separate. Had the implications of these observations been pursued, synthetic polymer chemistry conceivably might have evolved much earlier. But chemistry did not, for one reason or another, undergo development in this direction. 

Alternatively, we could consider inflating the tyre with a series of, say, 100 short steps - each separated by a short pause. The difference in pressure before and after each of these small steps would be so slight that the gas within the tyre would be allowed to reach equilibrium with its surroundings after adding each increment, and before the next. Stated a different way, the difference between the pressure of the gas in the hand pump and in the tyre will always be slight. 

In addition to fragment and graph indexing of polymer information, the POLID-CAS YR system also makes use of two distinct vocabularies for non-structural terms. The first vocabulary is, in essence, a controlled vocabulary of hierarchically ordered terms (taxonomy), supplemented by a second, more fluid vocabulary, which is subject to constant editing. The latter is used to further enhance the controlled vocabulary, e.g., the term isomerization , which is part of the controlled vocabulary, could be defined further by the terms racemization , tautomerization or rotation isomerization . Annotation of this kind is only a short step away from techniques, which we now associate with the terms tagging and folksonomies and which are typical components of Web 2.0 systems. POLIDCASYR s controlled vocabulary is structured according to a number of semantic categories such... 

Construction of 1,3-diene moieties from alkynes and ethylene is a unique methodology for the synthesis of 1,3-dienes. Mori used this strategy for the synthesis of anolignan A. Two methylene groups from ethylene are introduced onto the alkyne carbon of 109 using Ig to give 1,3-diene 110. From this compound, short-step synthesis of anolignan A is achieved (Scheme 41). ... 

Intramolecular cyclopropanations of a-diazocarbonyl compounds have been widely utilized as a means of constructing complex polycyclic compounds stereoselectively in short steps (e.g. equation 98)187"198. The choice of the ligand of the Rh(II) catalyst, Rh2L4,... 

A convenient, short-step synthesis of enantiomerically pure 2-methylenecyclopropyl-methanol has been achieved by treating optically pure epichlorohydrin with methylenephosphorane (equation 146)325. Vinyl ketones are cyclopropanated with ( )-1-... 

From this it is but a short step to the realization that all forms of life and being are simply variations on a single theme we are all in fact one being doing the same thing in as many different ways as possible. As the French proverb... 

Corey and colleagues applied their catalyst to the asymmetric Henry (nitro aldol) reaction using chiral aminoaldehydes and the short-step synthesis of an HIV protease inhibitor (Scheme 3.9) [26]. Interestingly, a newly generated asymmetric center is controlled by the chiral catalyst and nitrogen substituents. 

It can be a short step from intrigue to panic. Psilocybin users can have bad trips where they may believe they are sinking into the floor or they are being suffocated or harmed by others. The primary effects of psilocybin last four to six hours. For an additional two to four hours many users find it difficult to sleep and continue to experience an altered reality. It is common within the next few days to experience mood swings. Also, due to the intense nature of the experience, it is common to have recurring thoughts or feelings for several days or weeks. 

During my time in Heidelberg, that is, earlier than 1936, we found, in the course of experiments to distill butyllithium under high vacuum, that the lithium alkyl smoothly decomposed into lithium hydride and 1-butene. In carrying out similar experiments with ethyllithium immediately after the war, Gellert and I (41) found firstly that the lower lithium alkyls were distillable under suitable conditions, and secondly that 1-butene was formed from ethylene in contact with ethyllithium. From this observation it was a very short step to discover the stepwise organometallic synthesis (42)... 

Interesting synthetic applications of the [4+4] and [4+4+4] cycloadditions are reported. A novel, short-step synthetic method of muscone (24) has been developed using complex 10 as a starting compound [7]. Insertion of allene to the Ni-carbon bond in 10 at low temperature gives the bis-7r-allylnickel 22. Then isonitrile is inserted to 22. When the reaction mixture is warmed, the 15-membered cyclic compound 23 is formed by reductive elimination, and conversion of 23 to muscone (24) is achieved by hydrolysis and subsequent hydrogenation in 43 % overall yield. 

The cyclic ylide intermediate 366, as a 1,3-dipole, is generated by intramolecular reaction of Rh-carbene with the ketone in 365, and undergoes cycloaddition with n-bonds to give the adduct 367 [121]. When a-diazocarbonyls have additional unsaturation, domino cyclizations occur to produce polycyclic compounds. The Rh-carbene method offers a powerful tool for the construction of complex polycyclic molecules in short steps, and has been applied to elegant syntheses of a number of complex natural products. 

From the thesis that individual bodies are substances, however, it is a short step to the conclusion that body is a genus in the category of substance. If bodies are individual substances, to infer that body is a... 

Word-at-a-time conversion. This technique (flash converters) converts an analog input signal in a very short step (5 to 200 nsec) into digital form by comparing the input signal with all possible values at a time. Therefore a high number of comparators (2" 1, for a resolution of n bits) is needed to produce the result. As the number of comparators increases exponentially, this technique is limited to moderate resolution (typically 8 bit). 

I have done everything I can to avoid using the H word, but now that we have learned how to represent product operators in a matrix form it is a short step to working with the Hamiltonian. The Hamiltonian is a representation of the environment the spins find themselves in—it contains the energies of all of the interactions of spins with the B0 field, the B1 field, and with each other. 

These people had first taken it experimentally, because that was the only way it was given at all. Then it was just a short step for people who had taken it to say, "Let s try it [again] and to make up some circumstance which would... 

From this, it is a short step to the alternative definition of a spherical tensor operator... 

The latter has seemed promising enough to pursue. It has been seen that account must be taken of interactions which lead to association or clustering of defects and a tendency for longer range ordering. It is a short step to consider... 

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