Apparatus and method for solid phase synthesis

Abstract

An apparatus for microwave assisted solid phase synthesis using solid-phase resin beads mixed with a liquid solvent comprising a generally cylindrical reactor made of microwave transparent material and having a central axis, the reactor having an inlet and an outlet; a porous frit associated with the outlet of the reactor, the porous frit preventing discharge of beads and allowing discharge of the solvent from the reactor; and means for concentric rotation of the reactor around the central axis in alternating clockwise and anti-clockwise directions. A method for microwave assisted solid phase synthesis using the apparatus is also disclosed.

Claims

1. An apparatus for microwave assisted solid phase synthesis using solid-phase resin beads mixed with a liquid solvent, comprising: a generally cylindrical reactor vial, the reactor vial made of microwave transparent material, the reactor vial having a central axis, the central axis of the reactor vial extending through an interior of the reactor vial, the reactor vial having an inlet and an outlet; a porous frit, the porous frit closing the outlet of the reactor vial, the porous frit configured to prevent discharge of the resin beads from the reactor vial, the porous frit configured to drain the solvent from the reactor vial; and a mixer motor vertically beneath the reactor vial, such that a central axis of the mixer motor is aligned with the central axis of the reactor vial; and a control unit configured to control the mixer motor to rotate the reactor vial concentrically around the central axis of the reactor vial in alternating clockwise and anti-clockwise directions, such that the reactor vial is only rotated around the central axis extending through the interior of the reactor vial and is not shaken.

2. The apparatus according to claim 1, wherein the frit is configured to drain the solvent from the reactor vial, based on a vacuum being applied to the outlet.

3. The apparatus according to claim 1, wherein the frit has a pore size from about 1 to about 50 m.

4. The apparatus according to claim 3, wherein the frit has a pore size from about 5 to about 30 m.

5. The apparatus according to claim 1, wherein the frit is made of a hydrophobic material.

6. The apparatus according to claim 5, wherein the frit is made of PTFE.

7. A method for microwave assisted solid phase synthesis, comprising: providing an apparatus according to claim 1, wherein the reactor vial contains functionalized resin beads, a solvent and reactants for solid phase synthesis; subjecting the reactor vial to microwave heating; and mixing the contents of the reactor vial by rotating the reactor vial concentrically around the central axis of the reactor vial in alternating clockwise and anti-clockwise directions, such that the reactor vial is only rotated around the central axis extending through the interior of the reactor vial and is not shaken.

8. The method according to claim 7, wherein, the reactants for solid phase synthesis are reactants for solid phase peptide synthesis, and the solid phase synthesis is solid phase peptide synthesis.

9. The apparatus according to claim 1, wherein the reactor vial is arranged essentially vertical.

Description

BRIEF DESCRIPTION OF THE APPENDED DRAWING

(1) FIG. 1 is a perspective view of an embodiment of the apparatus for microwave-assisted solid phase synthesis according to the present invention.

DETAILED DESCRIPTION OF THE INVENTION

(2) As mentioned above, the present invention relates to an apparatus for microwave assisted solid phase synthesis, such as peptide synthesis, oligonucleotide synthesis or other organic synthesis.

(3) FIG. 1 shows an embodiment of the apparatus which is a part of a system microwave-assisted solid phase synthesis, the rest of the system not being shown in the FIGURE. Referring to FIG. 1, a reactor vial 1, to be filled with resin beads and solvent liquid, is mounted to a rotatable tubular shaft 2 supported by a support 3 and connected to a mixer motor 4. The reactor vial 1, which is made of a microwave-transparent material, e.g. polypropene (PP), has a top inlet 5 and a bottom outlet 6. The outlet 6 is closed by a frit 8, e.g. of polytetrafluorethylene (PTFE) or similar hydrophobic material, to hold the resin beads and the liquid in the reactor. The frit generally has a pore size between about 1 m and about 50 m, preferably between about 5 m and about 30 m. Through the tubular shaft 2, the reactor outlet 6 is connected to a drain outlet 7. Draining of liquid from the reactor 1 to the outlet 7 is typically effected by suction, e.g. via a vacuum pump (not shown).

(4) The support 3 is mounted in the system for microwave-assisted solid phase synthesis such that the reactor vial 1 is received in a microwave cavity thereof for microwave heating of the resin beads in the reactor vial.

(5) The mixer motor 4 is controlled by a control unit (not shown) by which desired angular displacements and rotation speeds of the motor can be set. The operation of the mixing apparatus is as follows.

(6) Through control of the control unit, the mixer motor 4 spins the reactor vial 1 about its centre axis in a non-continuous fashion. The spinning reactor vial forces its content of resin and reagents to also start rotating. After a given time, the direction of the rotation of the reactor vial 1 is reversed which forces a turbulence in the resin/reagent mix before it catches up with the reactor vial movement again. This procedure is then repeated. This turbulence caused by the repeated reversal of the rotational direction has a mixing effect.

(7) Compared to the conventional vortex mixing, there are two major benefits of rotation about the central axis in alternating directions, viz. (i) a larger reactor can be used (more efficient use of the microwave cavity volume), and (ii) a greater working volume is permitted (substantially reduced surface turbulence and splashing). Preferably the reactor vial 1 is arranged essentially vertical, preferably also essentially parallel to the rotatable tubular shaft 2, so that the maximum working volume is permitted.

(8) A typical workflow for an amino acid addition cycle in solid phase peptide synthesis is as follows: Place functionalized resin beads in the reactor (each bead, e.g. of polystyrene, supporting at least one protected amino acid or amino acid sequence) and swell with solvent and mix by actuating the mixer motor (4). Drain using vacuum via syringe outlet (7). Deprotect with solvent and mix by actuating the mixer motor (4), Drain using vacuum via syringe outlet (7). Couple amino acid during microwave heating and mix by actuating the mixer motor (4). Drain using vacuum via syringe outlet (7). Wash with solvent and mix by actuating the mixer motor (4). Drain using vacuum via syringe outlet (7). Repeat wash if needed.

(9) The reactor vial may be irradiated with microwaves to heat the reaction mixture at desired synthesis steps and/or during the concentric clockwise and anti-clockwise rotation.

(10) Typical reactor vial (1) volumes are in the range of about 10 to 30 mL.

(11) A typical rotation angle is about 720, and an exemplary frequency is about 0.5-1 cycles per second.

(12) Optionally, the rotation angle (angular excursion) in the clockwise direction is different from the rotation angle in the anti-clockwise direction.

(13) The present invention is not limited to the above-described preferred embodiments. Various alternatives, modifications and equivalents may be used. Therefore, the above embodiments should not be taken as limiting the scope of the invention, which is defined by the appending claims.