Propel lane

The kinetics of thermolysis for a set of propel-lanes has been studied and has been correlated with the decrease in strain energy on going to the corresponding diyl ... 

A series of dihalides (93) reacts with /-butyllithium at low temperature to give 94. The reactions apparently proceed by lithium-halogen exchange to produce the [3.1.1]propel-lane derivative 95 which adds /-butyllithium211. 

A closely comparable approach was utilized in the preparation of [3.3.3]propel-lane-3,7,10-trione (473, Scheme 70).408 ... 

Intramolecular exocyclic transannular cycloaddition of TMM can provide a viable route to propel-lanes, such as the sesquiteipene modhephene (144). TTiis methodology is demonstrated in an efficient synthesis of a [3.3.3]propellane (145) (equation 149)." The methylenecycloprtqtane approach is preferred in this case because it works well with dialkyl-substimted systems. 

Malamidou-Xenikaki E, Coutouli-Argyropoulou E (1992) Synthesis of heterocyclic propel-lanes by 1,3-dipolar cycloaddititm of 2,6-dichlorobenzonitrile oxide to 2,3-fused indoles. Catalytic hydrogenation of the cycloadducts. Liebigs Ann Chem 75-78... 

These and many other syntheses of the parent and derivatives have been reviewed [10]. The best route to 1 is perhaps reduction of the readily-available[ 1.1.1] propel-lane 2 (below) [11]. Bicyclo[l.l.l]pentane, a liquid with an estimated boiling point of 36°C, is very stable thermally heating it at 305° C for 9 hours gave a 1 1 mixture of the starting compound and 1,4-pentadiene [5, 6],... 

Fig. 13.4 MP2/6 geometries and central-C-C bond orders of [1.1.1]-, [2.1.1]- and [2.2.1]propel-lane. The bond orders are Lowdin [29] HF/6-31G on the MP2 geometries. Bond lengths are in A and angles in degrees...

Politzer P, Concha MC, Grice ME, Murray JS, Lane P, Habibollazadeh D (1998) Computational investigation of the structures and relative stabilities of amino/nitro derivatives of ethylene. J Mol Struc 452 77, reprinted with permission from Elsevier Sorescu DC, Boatz JA, Thompson DL (2001) J Phys Chem A 105 5010 Ji G-F, Xiao H-M, Dong H-S, Gong X-D, Li J-S, Wang Z-Y (2001) Acta Chim Sin 59 39 Grice ME, Habibollahzadeh D, Politzer P (1994) J Chem Phys 100 4706 Zeman S (1997) Themochim Acta 302 11 Zeman S (1999) J Ener Mater 17 305 Zeman S (1999) Themochim Acta 333 121 Zeman S, Krupka M (2003) Propell Explos Pyrotech 28 301... 

Apart from waves and currents dredging operations can be hindered by shipping. This applies to all plant but particularly to plant that is not self-propelled. Locating of borrow areas within shipping lanes should be avoided. However, this may not always be possible especially when the fill material has to be retrieved from the maintenance or deepening of a navigation channel. 

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