Abstract: A process for the preparation of a compound of formula R1—Y1—P(NR2R3)2 is provided. The process comprises reacting a compound of formula PX3 with a compound of formula HNR2R3 to form a compound of formula X—P(NR2R3)2; and reacting the compound of formula X—P(NR2R3)2 with a compound of formula R1—Y1—H in the presence of a hydrocarbon solvent to form the compound of formula R1—Y1—P(NR2R3)2. R1 represents a phosphorus protecting group; R2 and R3 each independently represent an alkyl, prefer-ably a C1-6alkyl, group, or R2 and R3 are joined, together with the N to which they are attached, to form a 5-7 membered ring; Y1 represents O or S, preferably O; and X represents a halogen, preferably Cl. The preferred solvent is toluene.

Abstract: This invention is directed toward providing a transatmospheric launch system that is essentially totally reusable, provides wide flexibility in choice of orbit, and may be launched quickly on short notice. The system of the invention is a two-stage horizontal takeoff and landing system. An orbiter vehicle (50) is integrated into the underside of an aircraft (2). Aircraft (2) has a cavity (4) opening aftwardly and downwardly to receive vehicle (50). Vehicle (50) and aircraft (2) are releasably connected by struts (30, 32). Aircraft (2) and vehicle (50) proceed to staging conditions under air breathing and then rocket power. Rocket engine (22) of aircraft (2) is throttled to produce a thrust differential with rocket engine (66) of vehicle (50). This differential causes vehicle (50) to automatically pivot away from aircraft (2) on struts (30, 32). After pivoting out of cavity (4), vehicle (50) is disengaged from struts (30, 32) and proceeds on its own to orbit. Aircraft (2) makes a conventional landing.